阅读说明：本技术 改善了效率的热泵 (Heat pump with improved efficiency ) 是由 李东源 于 2019-10-07 设计创作，主要内容包括：本发明涉及热泵。更详细而言,针对以多负载条件测量效率的热泵,涉及一种在各负载条件下设置目标高压与目标低压,最优先达成所述目标压力的热泵。尤其涉及一种改善了效率的热泵,如果负载随着时间而缓慢变化,则缓慢控制压缩机与负载相符,耗电的变动小。(The present invention relates to heat pumps. More specifically, the present invention relates to a heat pump in which a target high pressure and a target low pressure are set under each load condition, and the target pressure is most preferentially achieved in a heat pump in which efficiency is measured under a plurality of load conditions. More particularly, the present invention relates to a heat pump having improved efficiency, in which if a load is changed slowly with time, a compressor is controlled slowly in accordance with the load, and variation in power consumption is small.)

1. A heat pump comprising a circuit of a variable capacity compressor (C), a condenser (HEX _ C), an expansion valve (EXV) and an evaporator (HEX _ E) connected by a closed refrigerant line, the heat pump comprising a condenser fan (FN _ C), an evaporator fan (FN _ E), a refrigerant (filling) amount adjusting means (RAAM) for filling refrigerant into the circuit or recovering refrigerant from the circuit, and a controller (224),

the controller (224) functions including: 1) setting a target pressure inside the outdoor heat exchanger (HEX _ EX) with reference to an outside air temperature and a load, 2) setting a target pressure inside the indoor heat exchanger (HEX _ IN) with reference to an inside default air temperature and a set temperature, 3) setting a target supercooling degree (SC _ t) and a target superheating degree (SH _ t), 4) controlling so as to achieve one of adjustment of the overall temperature of the two fans or adjustment of the overall pressure;

4a) when the temperatures of the two fans are adjusted, the degree of Supercooling (SC) is adjusted by the condenser fan (FN _ C), the degree of Superheat (SH) is adjusted by the evaporator fan (FN _ E), the High Pressure (HP) is adjusted by one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM), and the Low Pressure (LP) is adjusted by the other (LP) [ case (a) (a') ]);

4b) when the pressures of the two fans are adjusted, the condenser fan (FN _ C) adjusts the High Pressure (HP), the evaporator fan (FN _ E) adjusts the Low Pressure (LP), one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) adjusts the supercooling degree (SC), and the other one adjusts the superheat degree (SH) [ case (b) (b') ];

5) controlling the compressor (C) with reference to a load so that a predetermined refrigerant (g/s) is compressed per unit time; as time goes from 0 to 24, if the load changes slowly, the power consumed by the heat pump also changes slowly in a similar fashion to the load.

2. A heat pump comprising a circuit of a variable capacity compressor (C), a condenser (HEX _ C), an expansion valve (EXV) and an evaporator (HEX _ E) connected by a closed refrigerant line, the heat pump comprising a condenser fan (FN _ C), an evaporator fan (FN _ E), a refrigerant (filling) amount adjusting means (RAAM) for filling refrigerant into the circuit or recovering refrigerant from the circuit, and a controller (224),

the controller (224) functions including: 1) setting a target pressure inside the outdoor heat exchanger (HEX _ EX) with reference to an outside air temperature and a load, 2) setting a target pressure inside the indoor heat exchanger (HEX _ IN) with reference to an inside air temperature and a set temperature, 3) setting a target supercooling degree (SC _ t) and a target superheating degree (SH _ t), 4) controlling such that one of the two fans adjusts the pressure and the other one adjusts the temperature;

4a) when the evaporator fan (FN _ E) adjusts the Low Pressure (LP), the condenser fan (FN _ C) adjusts the supercooling degree (SC), one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) adjusts the High Pressure (HP), and the other one controls the superheat degree (SH) [ case (d) (d') ];

4b) when the condenser fan (FN _ C) adjusts the High Pressure (HP), the evaporator fan (FN _ E) adjusts the superheat degree (SH), one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) adjusts the Low Pressure (LP), and the other one controls the supercooling degree (SC) [ case (E) (E') ];

5) controlling the compressor (C) with reference to a load so that a predetermined refrigerant (g/s) is compressed per unit time; as time goes from 0 to 24, if the load changes slowly, the power consumed by the heat pump also changes slowly in a similar fashion to the load.

3. The heat pump according to claim 1 or 2,

the refrigerant (filling) amount adjusting means (RAAM) includes a storage space (RS) for storing a refrigerant, a recovery valve (vvd) for recovering the refrigerant from the circuit to the refrigerant storage space (RS), and a filling valve (vvc) for filling the refrigerant from the refrigerant storage space (RS) to the circuit;

a refrigerant filling and recovery means (RCRM) is installed in parallel with the expansion valve (EXV);

the recovery valve (vvd) is connected with the outlet of the condenser (HEX _ C);

the filling valve (vvc) is connected to a low pressure.

4. The heat pump of claim 3,

the controller (224) performs control for increasing or decreasing the opening degrees of the recovery valve (vvd) and the filling valve (vvc) at the same time, so that the refrigerant (filling) amount adjusting means (RAAM) has the function of the expansion valve (EXV) as well.

5. A heat pump comprising a circuit of a variable capacity compressor (C), a condenser (HEX _ C), an expansion valve (EXV) and an evaporator (HEX _ E) connected by a closed refrigerant line, the heat pump comprising a condenser fan (FN _ C), an evaporator fan (FN _ E), a refrigerant (filling) amount adjusting means (RAAM) for filling refrigerant into the circuit or recovering refrigerant from the circuit, and a controller (224),

the controller (224) uses a target condensing temperature (HP _ t) and a target evaporating temperature (LP _ t) which are corrected by a curve in a temperature range in which an energy consumption efficiency (hereinafter, referred to as "CSPF") during cooling is calculated;

the curve is shown on the side of the low outside air temperature in the model of fig. 12 in the coefficient of performance table;

in the table, the curve ("evaporation temperature curve correction on the low-outside-air side") is displayed on the right side of a straight line connecting the first point (target evaporation temperature out of the maximum outside-air temperatures used for the CSPF calculation) and the second point (target evaporation temperature out of the minimum outside-air temperatures used for the CSPF calculation).

Technical Field

The invention relates to a Heat pump (Heat pump) with improved efficiency.

Background

A heat pump is a device that transfers heat from a heat source to a destination called a "heat sink. Heat pumps absorb heat in cold spaces and release heat to hot spaces. Air Conditioning apparatuses (HVAC) including an Air conditioner and a refrigerator are representative examples of the heat pump. Further, apparatuses using the heat pump are water purifiers, dryers, washing machines, vending machines, etc. that supply cold/hot water.

The heat pump includes a compressor, a condenser, an expansion valve, and an evaporator. Generally, the known air conditioner consumes about 20 times more power than the electric fan. If calculated on this basis, the compressor consumes 90% of the power, and the condenser fan and the evaporator fan consume 5% of the power, respectively.

In the prior art, an inverter compressor is used to reduce power consumption of the compressor, and if the load is small, the inverter compressor is operated at a low frequency. If the difference between the compressor inlet pressure and outlet pressure increases, the compressor consumes more power even if operated at the same frequency. The refrigeration period energy consumption efficiency (CSPF) and the integrated refrigeration efficiency (IEER) measured under the multi-load condition improve the heat pump efficiency only if the target low pressure and the target high pressure are actively achieved, although the inlet pressure and the outlet pressure of the compressor are not set to the most preferred achievement target for control in the past, and thus there is a problem of low efficiency.

Further, in US2009/00137001 and KR 10-2016-.

< prior patent document >

Application number KR 10-2007-7009952(US2009/0013700A1)

Application number KR10-2016-

Application No. KR 10-2013-

Application No. KR10-2016 Across 7026740(US 2016/0370044A 1)

Application No. 10-2007 & Puff 0084960

US 2011/0041523 A1

US 7,010,927 B2

US 9,738,138 B2

US 2017/0059219 A1

US 2017/0115043 A1

< prior non-patent document >

Myung Sup Yoon、Jae Hun Lim、Turki Salem M AL Qahtani、and YujinNam、“Experimental study on comparison of energy consumption between constant and variable speed air-conditioners in two different climates””,Asian Conference on Refrigeration and Air-conditioning June 2018,Sapporo,JAPAN

Disclosure of Invention

Technical problem

For a heat pump whose efficiency is measured in multiple load conditions, a target high pressure and a target low pressure are set at each load condition so that the target pressure is achieved with highest priority. Further, it is an object to provide a heat pump which can improve efficiency by achieving a target pressure without using a compressor having large power consumption.

Means for solving the problems

The heat pump of the present invention includes a circuit in which a variable capacity compressor (C), a condenser (HEX _ C), an expansion valve (EXV), and an evaporator (HEX _ E) are connected by a closed refrigerant line, and includes a condenser fan (FN _ C), an evaporator fan (FN _ E), a refrigerant (filling) amount adjusting means (RAAM) for filling or recovering a refrigerant into or from the circuit, and a controller 224, wherein the controller 224 functions to: 1) setting a target pressure inside the outdoor heat exchanger (HEX _ EX) with reference to an outside air temperature and a load, 2) setting a target pressure inside the indoor heat exchanger (HEX _ IN) with reference to an inside air temperature and a set temperature, 3) setting a target supercooling degree (SC _ t) and a target superheating degree (SH _ t), 4) controlling so as to achieve one of adjustment of the overall temperature of the two fans or adjustment of the overall pressure; 4a) when the temperatures of the two fans are adjusted, the degree of Supercooling (SC) is adjusted by the condenser fan (FN _ C), the degree of Superheat (SH) is adjusted by the evaporator fan (FN _ E), the High Pressure (HP) is adjusted by one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM), and the Low Pressure (LP) is adjusted by the other (LP) [ case (a) (a') ]); 4b) when the pressures of the two fans are adjusted, the condenser fan (FN _ C) adjusts the High Pressure (HP), the evaporator fan (FN _ E) adjusts the Low Pressure (LP), one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) adjusts the supercooling degree (SC), and the other one adjusts the superheat degree (SH) [ case (b) (b') ]; 5) controlling the compressor (C) with reference to a load so that a predetermined refrigerant (g/s) is compressed per unit time; as time goes from 0 to 24, if the load changes slowly, the power consumed by the heat pump also changes slowly in a similar fashion to the load.

The heat pump of the present invention includes a circuit in which a variable capacity compressor (C), a condenser (HEX _ C), an expansion valve (EXV), and an evaporator (HEX _ E) are connected by a closed refrigerant line, and includes a condenser fan (FN _ C), an evaporator fan (FN _ E), a refrigerant (filling) amount adjusting means (RAAM) for filling or recovering a refrigerant into or from the circuit, and a controller 224, wherein the controller 224 functions to: 1) setting a target pressure inside the outdoor heat exchanger (HEX _ EX) with reference to an outside air temperature and a load, 2) setting a target pressure inside the indoor heat exchanger (HEX _ IN) with reference to an inside air temperature and a set temperature, 3) setting a target supercooling degree (SC _ t) and a target superheating degree (SH _ t), 4) controlling such that one of the two fans adjusts the pressure and the other one adjusts the temperature; 4a) when the evaporator fan (FN _ E) adjusts the Low Pressure (LP), the condenser fan (FN _ C) adjusts the supercooling degree (SC), one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) adjusts the High Pressure (HP), and the other one controls the superheat degree (SH) [ case (d) (d') ]; 4b) when the condenser fan (FN _ C) adjusts the High Pressure (HP), the evaporator fan (FN _ E) adjusts the superheat degree (SH), one of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) adjusts the Low Pressure (LP), and the other one controls the supercooling degree (SC) [ case (E) (E') ]; 5) controlling the compressor (C) with reference to a load so that a predetermined refrigerant (g/s) is compressed per unit time; as time goes from 0 to 24, if the load changes slowly, the power consumed by the heat pump also changes slowly in a similar fashion to the load.

In this case, it is preferable that the refrigerant (filling) amount adjusting means (RAAM) includes a storage space (RS) for storing the refrigerant, a recovery valve (vvd) for recovering the refrigerant from the circuit to the refrigerant storage space (RS), and a filling valve (vvc) for filling the circuit with the refrigerant from the refrigerant storage space (RS); a refrigerant filling and recovery means (RCRM) is installed in parallel with the expansion valve (EXV); the recovery valve (vvd) is connected with the outlet of the condenser (HEX _ C); the filling valve (vvc) is connected to a low pressure.

Preferably, the controller 224 performs control to increase or decrease the opening degrees of the recovery valve (vvd) and the filling valve (vvc) at the same time, so that the refrigerant (filling) amount adjusting means (RAAM) also functions as the expansion valve (EXV).

The heat pump of the present invention comprises a loop of a variable capacity compressor (C), a condenser (HEX _ C), an expansion valve (EXV) and an evaporator (HEX _ E) connected by a closed refrigerant line, the heat pump comprising a condenser fan (FN _ C), an evaporator fan (FN _ E), a refrigerant (filling) amount adjusting means (RAAM) for filling the loop with a refrigerant or recovering the refrigerant from the loop, and a controller 224, wherein the controller 224 uses a target condensing temperature (HP _ t) and a target evaporating temperature (LP _ t) corrected by a curve within a temperature range in which an energy consumption efficiency (hereinafter referred to as "CSPF") during cooling is calculated; the curve is shown on the side of the low outside air temperature in the model of fig. 12 in the coefficient of performance table; in the table, the curve ("evaporation temperature curve correction on the low-outside-air side") is displayed on the right side of a straight line connecting the first point (target evaporation temperature out of the maximum outside-air temperatures used for the CSPF calculation) and the second point (target evaporation temperature out of the minimum outside-air temperatures used for the CSPF calculation).

ADVANTAGEOUS EFFECTS OF INVENTION

According to the heat pump control method of the present invention, there is provided a heat pump in which efficiency is measured under a plurality of load conditions, and a target high pressure and a target low pressure are set under each load condition so that the target pressure is achieved with a high priority. In addition, there is an effect of providing a heat pump that can improve efficiency by achieving a target pressure without using a compressor that consumes much power.

Drawings

FIG. 1 is an example of a p-h line graph of the prior art.

Fig. 2 is a diagram for assisting understanding of the first control to the fourth control of the present invention.

FIG. 3 is an example of a p-h line graph of the present invention.

Fig. 4 is an example of a control sequence of the present invention.

Fig. 5 is an example listing the kind of control sequence of the present invention.

Fig. 6 is an example of a heat pump circuit suitable for the present invention.

Fig. 7 is yet another example of a heat pump circuit suitable for the present invention.

Fig. 8 is yet another example of a heat pump circuit suitable for the present invention.

Fig. 9 is yet another example of a heat pump circuit suitable for the present invention.

Fig. 10 is a table in which the roles of the main components suitable for the present invention are arranged.

Fig. 11 is an example of calculating the preferred CSPF of the present invention.

Fig. 12 is yet another example of calculating a preferred CSPF of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. At this time, it is to be noted that the same constituent elements in the drawings are denoted by the same reference numerals as much as possible. In this specification, the singular forms also include the plural forms as long as they are not specifically mentioned in the sentence. The use of "comprising" and/or "comprising" in the specification does not exclude the presence or addition of one or more other elements, steps and/or actions than those listed.

In addition, terms or words used in the present specification and claims described below should not be construed as limited to general or dictionary meanings, but interpreted only as meanings or concepts conforming to the technical idea of the present invention. Moreover, detailed descriptions of well-known structures and functions that are judged to unnecessarily obscure the gist of the present invention are omitted.

In the following description, an ideal heat pump will be used for convenience, unless otherwise mentioned. At this time, the controller controls the components of the heat pump to adjust the performance of each component. In the following description, if there are descriptions of "adjust", "control", "controlled", etc., even if the controller is not mentioned independently, it means "the controller provides a control value so that the description is realized". In addition, the "control" executed by the controller may be a certain "action" or may be a certain "order". In the present specification, "control" should be interpreted as "action" unless specifically mentioned. It is to be noted that in the present specification, the term "pressure" may be interpreted as "a temperature at which the refrigerant boils at the pressure, i.e., a condensation temperature or an evaporation temperature".

< description of the main concept >

The heat exchanger can calculate the amount of heat exchange by Q ═ c · m · dT. Among them, many combinations of m and dT are used to make Q the same. In the above equation, m (for example, when the heat exchange material is air) can be interpreted as an air amount, an air weight, a wind speed, a heat exchanger fan speed, a fan power consumption, and the like. At this time, c is the air specific heat or the proportionality coefficient. The temperature difference dT (air temperature before passing through the heat exchanger — air temperature after passing) varies according to the temperature difference between the refrigerant boiling in the heat exchanger and the inflow air. In the present invention, the control of reducing dT may mean "control of reducing a temperature difference between a temperature at which the refrigerant boils inside the heat exchanger and a temperature of a substance (for example, air) to be heat-exchanged with the heat exchanger".

To describe in more detail, if the heat exchanger temperature (the temperature at which the refrigerant boils inside the heat exchanger) is the same as the air temperature, no heat exchange occurs. Therefore, one of the methods of reducing the temperature difference dT is to reduce the difference between the temperature of the air flowing into the heat exchanger and the temperature at which the refrigerant boils inside the heat exchanger (hereinafter referred to as "heat exchanger temperature"). For this purpose, the pressure inside the heat exchanger needs to be regulated.

In general, since the power consumption of the compressor is much greater than that of the fan, if the temperature difference dT is greater than or equal to a predetermined value, if the target heat exchange amount (Q ═ c · m · dT) is achieved by increasing m and decreasing dT, the overall power consumption is reduced, and the heat pump efficiency is improved.

< description of the elements >

The following description will be made with reference to fig. 1 and 2.

The refrigerant is injected into the heat pump system. After the heat pump pipe is installed, the interior of the pipe is vacuumized by a vacuum pump. And, connect the external (on the electronic scale) coolant barrel and low-pressure pipeline, start the compressor. If the valve of the external refrigerant barrel is opened, the refrigerant is filled into the heat pump from the external refrigerant barrel. If the refrigerant with the set weight is filled, the valve of the external refrigerant barrel is locked. Thus, high pressure and low pressure are suitably formed in the heat pump. For example as shown in the first refrigeration cycles (81) - (82) - (83) - (84). As can be seen, if the refrigerant is filled (hereinafter referred to as "first control"), both the High Pressure (HP) and the Low Pressure (LP) are increased (from vacuum to low pressure, and from vacuum to high pressure) (1). On the contrary, if the refrigerant is recovered (hereinafter referred to as "second control"), both the High Pressure (HP) and the Low Pressure (LP) are reduced (from low pressure to vacuum, from high pressure to vacuum) (2).

In other words, in a refrigeration circuit in which high and low pressures are appropriately formed, if a refrigerant is additionally charged from the outside to the low pressure of the circuit, the entire additional refrigerant is not only at the low pressure, but a part of the additional refrigerant moves to the high pressure (until the high and low pressures are stabilized). As can be seen, if the refrigerant is filled (i.e., if the first control is performed), both the High Pressure (HP) and the Low Pressure (LP) are increased (1). On the contrary, if the refrigerant is recovered (i.e., if the second control is performed), both the High Pressure (HP) and the Low Pressure (LP) are reduced (2).

In the state where the first refrigeration cycles (81) - (82) - (83) - (84) are formed, if an operation of further closing the expansion valve (hereinafter referred to as "third control" in which the difference between the high pressure and the low pressure increases) is performed, the High Pressure (HP) increases and the Low Pressure (LP) decreases (3), as can be shown in the second refrigeration cycles (91) - (92) - (93) - (94). The third control can also be achieved by driving the inverter compressor faster. In addition, in the state where the second refrigeration cycles (91) - (92) - (93) - (94) are formed, if an operation of further opening the expansion valve (hereinafter referred to as "fourth control" in which the difference between the high pressure and the low pressure is reduced) is performed, the High Pressure (HP) is reduced and the Low Pressure (LP) is increased (4), as can be shown in the first refrigeration cycles (81) - (82) - (83) - (84). The fourth control may also be implemented by driving the inverter compressor at a lower frequency. In this case, the expansion valve is preferably an Electronic Expansion Valve (EEV).

If the first control 1 or the second control 2 is performed, both the high pressure and the low pressure are increased (UU) or decreased (DD). If the third control 3 or the fourth control 4 is performed, the low pressure is decreased (d) if the high pressure is increased (u), and the low pressure is increased (u) if the high pressure is decreased (d). If the control of both pressures moving to one side is combined with the control of moving to the opposite side of each other, it is possible to adjust one side pressure while maintaining the other side pressure.

For example, if the first control 1 and the third control 3[1+3] are executed simultaneously or sequentially (irrespective of the order), the high pressure is increased and the low pressure is cancelled without change. In addition, if the first control 1 and the fourth control 4[1+4] are executed simultaneously or sequentially (irrespective of the sequence), the low pressure is increased and the high pressure is cancelled without being changed. In addition, if the second control 2 and the third control 3[2+3] are executed simultaneously or sequentially (regardless of the order), the low pressure is reduced and the high pressure is cancelled without being changed. In addition, if the second control 2 and the fourth control 4[2+4] are executed simultaneously or sequentially (irrespective of the order), the high pressure is reduced and the low pressure is cancelled without change. In this case, it is preferable to control the condenser fan and the evaporator fan so that the degree of supercooling and the degree of superheat become design values.

If the third control 3 and the fourth control 4[3+4] are executed simultaneously or sequentially (irrespective of the order), the refrigerant circulation amount per unit time can be adjusted without changing the higher pressure and the lower pressure. More specifically, if the amount of refrigerant compressed per unit time by the compressor is further increased in the third control 3, and the difference between the high pressure and the low pressure is further increased, and if the expansion valve is further opened in the fourth control 4, and the difference between the high pressure and the low pressure is further decreased, the amount of refrigerant (gram/sec, hereinafter referred to as "g/s") circulating in the circuit per unit time is further increased, although the high pressure and the low pressure are not changed. On the other hand, if the control targets of the third control and the fourth control are changed, the amount of refrigerant circulating in the circuit is further decreased.

The above description has been made of the element technology required for adjusting the pressure on the other side while maintaining the pressure on the one side. Note that in this specification, the high pressure may be interpreted as "a temperature at which the refrigerant boils at a high pressure", that is, "a condensation temperature", and the low pressure may be interpreted as "a temperature at which the refrigerant boils at a low pressure", that is, "an evaporation temperature".

< example 1>

One embodiment (air-conditioning cooling mode) of controlling so as to further increase the evaporation temperature in the heat pump of the present invention will be described below with reference to fig. 2 to 4.

Fig. 4 is an example of a sequence of controlling so as to further increase the evaporation temperature of the evaporator. The control sequence 100 is an example in which the fourth control 4 and the first control 1 are continuously performed 2 times. In the initial state (L0), the controller sets the target low pressure (LP _ t) higher than the present low pressure (LP _0) according to some need. Then, the low pressure is different from the target value, and the controller executes the fourth control 4 in order to make the low pressure the same as the target value. As a result, the low pressure rises and the high pressure falls, resulting in a state (L1). Although the low pressure is desirably increased and the evaporation temperature is further increased, the high pressure is decreased and the condensation temperature becomes lower than the target condensation temperature (HP _ t). If the controller executes the first control 1 so that the high pressure becomes equal to the target value (HP _ t), the refrigerant is filled, and both the high pressure and the low pressure rise to become a state (L2). That is, the evaporation temperature of the low pressure further rises closer to the target evaporation temperature (LP _ t), and the high pressure maintains the target condensation temperature (HP _ t). The states (L3) and (L4) illustrate the case where the fourth control 4 and the first control 1 are repeated one more time in this order. Then, the low pressure rises along (LP _ rise) to reach the target low pressure (LP _ t).

If the control sequence 100 is explained from the perspective of the controller, in the initial state (L0), the controller sets the target low pressure (LP _ t) higher than the present low pressure (LP _0) as necessary. The controller recognizes that the low pressure (LP _0) is lower than the target value (LP _ t) in the initial state (L0), and performs a fourth control 4 for further opening the expansion valve so that the low pressure is equal to the target value (LP _ t). As a result, the state is reached (L1). In the state (L1), the controller recognizes that the high pressure is lower than the target value, and performs the first control 1 for filling the refrigerant so that the high pressure becomes equal to the target value (HP _ t). As can be seen, the controller functions to adjust the expansion valve to achieve the target value if the low pressure deviates from the target value, and to adjust the refrigerant filling amount to achieve the target value if the high pressure deviates from the target value.

In fig. 4, the control sequence 101 uses the fourth control 4 and the first control 1 as in the control sequence 100, but is a case where the first control 1 is executed first. In the initial state (L0a), the controller sets the target low pressure (LP _ t) higher than the present low pressure (LP _0) according to some need. Then, the low pressure is different from the target value, and the controller executes the first control 1 in order to make the low pressure the same as the target value. As a result, the low pressure rises and the high pressure falls, resulting in a state (L1 a). Although the low pressure is desirably increased and the evaporation temperature is further increased, the high pressure is decreased and the condensation temperature becomes higher than the target condensation temperature (HP _ t). Here, if the controller executes the fourth control 4 in order to make the high pressure equal to the target value (HP _ t), the high pressure decreases and the low pressure increases, and the state becomes (L2 a). That is, the evaporation temperature of the low pressure further rises closer to the target evaporation temperature (LP _ t), and the high pressure maintains the target condensation temperature (HP _ t). The states (L3a) and (L4a) illustrate the case where the first control 1 and the fourth control 4 are repeated one more time in sequence. Then, the low pressure rises along (LP _ rise) to reach the target low pressure (LP _ t).

If the control sequence 101 is explained from the perspective of the controller, in the initial state (L0a), the controller sets the target low pressure (LP _ t) higher than the present low pressure (LP _0) according to some need. The controller recognizes that the low pressure (LP _0) is lower than the target value (LP _ t) in the initial state (L0a), and performs the first control 1 for filling the refrigerant so that the low pressure is equal to the target value (LP _ t). As a result, the state is set to (L1 a). In the state (L1a), the controller recognizes that the high pressure is higher than the target value, and executes the fourth control 4 for further opening the expansion valve so that the high pressure becomes equal to the target value (HP _ t). As can be seen, the controller functions to adjust the expansion valve to achieve the target value if the high pressure is deviated from the target value, and to adjust the refrigerant filling amount to achieve the target value if the low pressure is deviated from the target value.

If the control sequences 100 and 101 are briefly compared, both set the target low pressure (LP _ t) higher than now and achieve the target. In addition, the same first control 1 and fourth control 4 are used for both. However, the targets of the first control and the fourth control are changed from each other. The first control fills the refrigerant but is used to achieve a target high pressure on one side and a target low pressure on the other side. In other words, the same result can be obtained even if the order of the first control 1 and the fourth control 4 is changed. For this reason, the targets of the respective controls need to be replaced with each other.

As shown in the control sequences 100 and 101, the same effect can be obtained even if the first control 1 and the fourth control 4 are sequentially changed. Thus, in the present invention, the control sequence 100, if broadly explained, of course includes a control sequence 101. Note that the control sequences 150, 200, and 250 described below should also be broadly explained.

In fig. 5, a control sequence 200 is an example in which the first control 1 and the third control 3 are performed 2 times in succession. In the initial state (H0), the controller sets the target high voltage (HP _ t) higher than the present high voltage (HP _0) according to some need. Then, the high pressure is different from the target value, and the controller performs the first control 1 of filling the refrigerant in order to make the high pressure equal to the target value (HP _ t). As a result, both the high pressure and the low pressure rise, and the state is reached (H1). The high pressure is desirably increased and the condensing temperature becomes closer to the target condensing temperature (HP _ t). However, the low pressure also rises, and the evaporation temperature becomes higher than the target evaporation temperature (LP _ t). In order to make the low pressure equal to the target value (LP _ t), if the controller executes the third control 3 by the expansion valve, the difference between the high pressure and the low pressure is further increased, the high pressure is raised, the low pressure is lowered, and the state is reached (H2). That is, the high-pressure condensation temperature further rises closer to the target condensation temperature (HP _ t), and the low-pressure maintains the target evaporation temperature (LP _ t). The states (H3) and (H4) illustrate the first control 1 and the third control 3 being sequentially repeated 1 more times. Then, the high voltage edge (HP _ rise) rises, reaching the target high voltage (HP _ t).

If the control sequence 200 is explained from the perspective of the controller, in the initial state (H0), the controller sets the target high pressure (HP _ t) higher than the present high pressure (HP _0) as desired. Then, the high pressure is different from the target value, and the controller performs the first control 1 for filling the refrigerant so that the high pressure is equal to the target value (HP _ t). As a result, the state is reached (H1). In the state (H1), the controller recognizes that the low pressure is higher than the target value, and executes a third control 3 for further closing the expansion valve so that the low pressure becomes equal to the target value (LP _ t). As can be seen, the controller is operative to adjust the refrigerant filling amount to achieve the target if the high pressure is off the target, and to adjust the expansion valve to achieve the target if the low pressure is off the target. In the control sequence 200, if the sequence of the first control 1 and the third control 3 is changed, the controller naturally needs to adjust the low pressure by the refrigerant filling amount and adjust the high pressure by the expansion valve.

In fig. 5, the control sequence 150 is an example in which the third control 3 and the second control 2 are performed 2 times in succession. In the initial state (L5), the controller sets the target low pressure (LP _ t) lower than the present low pressure (LP _0) according to some need. Then, the low pressure is different from the target value, and the controller performs the third control 3 through the expansion valve in order to make the low pressure the same as the target value (LP _ t). As a result, the high pressure rises and the low pressure falls, and the state is reached (L6). The low pressure desirably decreases and the evaporation temperature becomes lower, but the high pressure increases and the condensation temperature becomes higher than the target condensation temperature (HP _ t). If the controller executes the second control 2 so that the high pressure becomes equal to the target value (HP _ t), the refrigerant is recovered, and both the high pressure and the low pressure drop to become a state (L7). That is, the evaporation temperature of the low pressure further decreases, closer to the target evaporation temperature (LP _ t), and the high pressure maintains the target condensation temperature (HP _ t). The states (L8) and (L9) illustrate the case where the third control 3 and the second control 2 are sequentially repeated 1 more times. Then, the low pressure edge (LP _ fall) falls to reach the target low pressure (LP _ t).

If the control sequence 150 is explained from the perspective of the controller, in the initial state (L5), the controller sets the target low pressure (LP _ t) lower than the present low pressure (LP _0) as desired. The controller recognizes that the low pressure (LP _0) is higher than the target pressure (LP _ t) in the initial state (L5), and performs a third control 3 for further closing the expansion valve so that the low pressure is equal to the target pressure (LP _ t). As a result, the state is reached (L6). In the state (L6), the controller recognizes that the high pressure is higher than the target value, and executes the second control 2 for recovering the refrigerant so that the high pressure becomes equal to the target value (HP _ t). As can be seen, the controller is operative to adjust the expansion valve to achieve the target if the low pressure is off the target, and to adjust the refrigerant charge amount to achieve the target if the high pressure is off the target. On the other hand, if the order of the second control 2 and the third control 3 is changed in the control sequence 150, the controller naturally needs to adjust the low pressure by the refrigerant filling amount and the high pressure by the expansion valve.

In fig. 5, the control sequence 250 is an example in which the second control 2 and the fourth control 4 are performed 2 times in succession. In the initial state (H5), the controller sets the target high pressure (HP _ t) lower than the present high pressure (HP _0) according to some need. Then, the high pressure is different from the target value, and the controller executes the second control 2 for recovering the refrigerant so that the high pressure is equal to the target value (HP _ t). As a result, both the high pressure and the low pressure drop, and the state is reached (H6). The high pressure is desirably reduced and the condensing temperature is closer to the target condensing temperature (HP _ t). However, the low pressure also drops, and the evaporation temperature becomes lower than the target evaporation temperature (LP _ t). If the controller executes the fourth control 4 so that the low pressure becomes equal to the target value (LP _ t), the difference between the high pressure and the low pressure becomes smaller, the high pressure falls, and the low pressure rises, resulting in a state (H7). That is, the high-pressure condensation temperature further decreases closer to the target condensation temperature (HP _ t), and the low-pressure maintains the target evaporation temperature (LP _ t). The states (H8) and (H9) illustrate the case where the second control 2 and the fourth control 4 are sequentially repeated 1 more times. Then, the high voltage edge (HP _ fall) falls to reach the target high voltage (HP _ t).

If the control sequence 250 is explained from the perspective of the controller, in the initial state (H5), the controller sets the target high pressure (HP _ t) lower than the present high pressure (HP _0) as desired. Then, the high pressure is different from the target value, and the controller executes the second control 2 for recovering the refrigerant so that the high pressure is equal to the target value (HP _ t). As a result, the state is reached (H6). In the state (H6), the controller recognizes that the low pressure is lower than the target value, and executes fourth control 4 for further opening the expansion valve so that the low pressure becomes equal to the target value (LP _ t). It can be known that the controller is used for adjusting the expansion valve to achieve the target if the low pressure is deviated from the target, and adjusting the refrigerant filling amount to achieve the target if the high pressure is deviated from the target. In short, the controller regulates the low pressure by the expansion valve and the high pressure by the refrigerant filling amount. In the control sequence 250, if the sequence of the second control 2 and the fourth control 4 is changed, the controller naturally needs to adjust the low pressure by the refrigerant filling amount and adjust the high pressure by the expansion valve.

The conventional air conditioner is operated to some extent, and when the cooling load is reduced (that is, the required heat exchange amount is reduced) (or when the load is reduced due to a decrease in the outside air temperature), the outdoor unit fan (FN _ EX) is rotated at the maximum speed or less. At this time, when the heat exchange temperature difference in the condenser is large, it is preferable to lower the condensing temperature while maintaining the evaporating temperature in the control sequence 250 of the present invention. Accordingly, while maintaining the heat exchange amount (Q ═ c · m · dT) of the outdoor heat exchanger (HEX _ EX) at a predetermined value corresponding to the load size, dT is decreased, m is increased, and the power consumption of the air conditioner can be reduced.

IN a conventional air conditioner, when a cooling load is reduced (that is, a heat exchange request amount is reduced), an indoor unit fan (FN _ IN) is rotated at a maximum speed or less. In this case, when the heat exchange temperature difference in the evaporator is large, it is preferable to increase the evaporation temperature while maintaining the condensation temperature in the control sequence 100 of the present invention. Therefore, dT can be reduced and m can be increased while keeping the heat exchange amount (Q ═ c · m · dT) of the indoor heat exchanger (HEX _ IN) at the load level, thereby reducing the power consumption of the air conditioner.

In this case, increasing m can be interpreted as "further increasing the rotation speed of the fan" or "further increasing the weight of air transferred per unit time". In addition, decreasing dT actually includes decreasing the power consumption of the compressor (for example, decreasing the driving frequency of the inverter compressor), and decreasing the difference between the high pressure and the low pressure without independently controlling the compressor [ as a result of the control sequence 250 or as a result of the control sequence 100 ], thereby decreasing the power consumption of the compressor.

When the high pressure is lowered while the supercooling degree (SC) is kept at a predetermined value, the amount of heat exchanged in the evaporator (HEX _ E) by the refrigerant per unit weight is increased. If explained in more detail, if the high pressure is lowered while keeping the (low pressure and) degree of Supercooling (SC) at a prescribed value, i.e., if the control sequence 250 is executed, the distance of the saturated liquid point from the saturated vapor point becomes farther under the (p-h line graph) high pressure. As a result, more heat exchange can be performed in the (indoor/outdoor) heat exchanger using the same amount of refrigerant. In this case, if the required amount of heat exchange (cooling or heating) is not changed, 1) the refrigerant circulation amount per unit time (g/s) can be reduced (for example, the driving frequency of the inverter compressor is reduced), and the power consumed by the compressor can be reduced. And 2) the pressure difference across the compressor is reduced, the power consumed by the compressor can be reduced.

Further, if the low pressure is increased in a state where the degree of Superheat (SH) is maintained at a predetermined value, the refrigerant density increases at the low pressure, the refrigerant circulation amount per unit time (g/s) increases, and the amount of heat that can be exchanged in the (indoor/outdoor) heat exchanger increases. In this case, if the required amount of heat exchange (cooling or refrigeration) is not changed, 1) the refrigerant circulation amount (g/s) per unit time can be reduced (for example, the inverter compressor driving frequency is reduced) to reduce the power consumed by the compressor, and 2) the pressure difference between both ends of the compressor is reduced to reduce the power consumed by the compressor.

Therefore, if the control sequence 100 and/or 250 is executed in the case where the load is less than the rated value and dT is greater than the predetermined value, the efficiency of the heat pump is improved. Of course, the target high pressure (HP _ t) and the target low pressure (LP _ t) which are preferable under various conditions (for example, the outside air temperature, the installation temperature, the indoor air temperature, and the like) can be obtained by a plurality of preceding experiments.

The heat pump control concept of the invention can of course also be applied to refrigeration. Therefore, the "target evaporation temperature" of the cooling mode explained IN the present specification is preferably interpreted as "heat exchange temperature of the indoor heat exchanger (HEX _ IN)". Also, the "target condensing temperature" is preferably interpreted as "outdoor heat exchanger (HEX _ EX) heat exchange temperature".

< example 2>

Referring now to fig. 6, an example of a heat pump 600 suitable for the present invention is illustrated.

The heat pump 600 includes a "circuit" in which a compressor (C), a condenser (HEX _ C), an expansion valve (EXV), and an evaporator (HEX _ E) are connected by a closed refrigerant line. Furthermore, a refrigerant storage tank (RS1) is installed in parallel with the expansion valve (EXV). A recovery valve (vvd) for recovering refrigerant in a "circuit" is provided between the inlet of the expansion valve (EXV) and the inlet of the tank (RS 1). A filling valve (vvc) for filling the refrigerant into the "circuit" is provided between the outlet of the expansion valve (EXV) and the outlet of the tank (RS 1). The refrigerant storage tank (RS1), the recovery valve (vvd), and the fill valve (vc) are hereinafter referred to as "refrigerant (fill) amount adjustment means (RAAM)" in a bundle.

An example of filling the refrigerant when the heat pump 600 is installed will be described below. First, after the heat pump 600 piping is installed, the valve (EXV) (vvd) (vvc) is opened, and the "circuit" and the refrigerant storage tank (RS1) are evacuated by the external vacuum pump. Furthermore, the recovery valve (vvd) and the fill valve (vvc) are completely closed. The external refrigerant tank of the heat pump 600 is connected to the loop, and the compressor (C) is started. Then, if the external refrigerant tank valve is opened, the heat pump 600 is filled with the refrigerant from the external refrigerant tank. After the refrigerant with the designed quantity is filled, the valve of the external refrigerant barrel is completely locked.

Next, the second control 2 for recovering the refrigerant in the "circuit" of the heat pump 600 and storing the refrigerant in the refrigerant storage tank (RS1) will be described. When the refrigerant recovery valve (vvd) is opened, the condensed refrigerant expands while being recovered from the loop to the storage tank (RS1) because the high pressure of the loop is high and the inside of the storage tank (RS1) is vacuum. If a predetermined amount of refrigerant is recovered in the tank (RS1) (the high pressure is the same as the pressure inside the tank), further recovery of refrigerant is not possible. At this time, if the refrigerant charge valve (vvc) connected to the low pressure is slightly opened to discharge the expanded refrigerant in the tank (RS1), the pressure in the tank (RS1) is lowered, and the condensed refrigerant continues to be recovered.

The first control 1 for filling the "circuit" of the heat pump 600 with the refrigerant will be described below. When the recovery valve (vvd) is closed and the filling valve (vvc) is opened, the refrigerant in the refrigerant storage tank (RS1) is moved by the suction force of the compressor and is filled into the 'circuit'. Finally, the refrigerant fills the "loop" until the low pressure line pressure is the same as the refrigerant storage tank (RS1) internal pressure.

In this embodiment, the descriptions of the third control 3 and the fourth control 4 have been described in detail in the description of the element technology of the present invention, and thus are omitted. As described above, the first control 1 to the fourth control 4, which are the techniques of the elements of the present invention, can be applied to the heat pump 600.

The heat pump 700 of fig. 7 exemplarily illustrates a case where the refrigerant charging valve (vvc) is installed between the storage tank (RS2) and the inlet of the compressor (C).

The heat pump 800 of fig. 8 is the heat pump 600 of fig. 6, in which the expansion valve (EXV) is removed, the refrigerant storage tank (RS1) is changed to a gas-liquid separable storage tank (RS3), and the gas inside the gas-liquid separator (RS3) is injected (more broadly, referred to as "supply") into the compressor (C). At this time, the control of simultaneously increasing or simultaneously decreasing the opening degrees of the recovery valve (E _ vvd) and the filling valve (E _ vvc) is performed, and an expansion valve (EXV) function is performed. The refrigerant filling and recovery can be realized by the same principle as the heat pump 600, and thus a detailed description thereof is omitted.

The refrigerant (filling) amount adjusting means (RAAM) of fig. 6 to 8 should be construed as being installed in parallel with the expansion valve (EXV).

< example 3>

Referring now to fig. 6, an example of a method for controlling a cooling mode of a heat pump 600 suitable for the present invention is described. The circuit configuration of the heat pump 600 has been described above and is therefore omitted. In the present invention, the controller 224 preferably includes the following first to seventh roles.

1) Variable displacement compressor control: the controller 224 controls the compressor (C) to compress the set amount of refrigerant (g/s) per unit time. The compression amount (g/s) may be calculated with reference to a refrigeration load. In the case of the inverter compressor (C), the compressor is operated at a frequency set in accordance with the load. If the low pressure and the degree of Superheat (SC) are kept predetermined, the density of the refrigerant is predetermined under the condition, and the amount of refrigerant (g/s) compressed per unit time by the compressor (C) is calculated at the driving frequency (hereinafter referred to as "amount of refrigerant compression per unit time"). In the present invention, a compressor having a variable compression stroke distance may of course be used.

2) Condenser fan speed control: the controller 224 controls the speed of the condenser fan FN _ C so that the supercooling degree SC of the refrigerant measured at the outlet of the condenser HEX _ C becomes the target supercooling degree SC _ t. (hereinafter referred to as "control of supercooling degree by condenser fan")

3) Evaporator fan speed control: the controller 224 controls the speed of the evaporator fan FN _ E so that the Superheat (SH) of the refrigerant measured at the outlet of the evaporator HEX _ E becomes the target superheat (SH _ t). (hereinafter referred to as "superheat degree control by evaporator fan")

4) Controlling the opening degree of an expansion valve: if the expansion valve (EEV) is opened further than now, the high pressure drops and the low pressure rises. Conversely, if the expansion valve (EEV) is closed further than now, the high pressure rises and the low pressure falls. In the present invention, the controller 224 controls the expansion valve (EXV) so that one of the two pressures becomes a target pressure. Hereinafter, the case where the controller 224 adjusts the low pressure by the expansion valve as the highest priority to achieve the target is referred to as "low pressure control by the expansion valve". The case where the high pressure is regulated as the highest priority to achieve the target is referred to as "high pressure control by the expansion valve". For this purpose, the expansion valve (EXV) is preferably an Electronic Expansion Valve (EEV).

5) Refrigerant (filling) amount adjusting means (RAAM) control: if the circuit is filled with the refrigerant, both the high pressure and the low pressure rise, and if the refrigerant is recovered, both the high pressure and the low pressure fall. In the present invention, the controller 224 controls the refrigerant (filling amount) adjusting means so that one of the two pressures becomes the target pressure. Hereinafter, the case where the controller adjusts the high pressure by the refrigerant (filling amount) adjusting means as the highest priority to achieve the target is referred to as "high pressure control by the refrigerant (filling) amount adjusting means (RAAM)". The case where the target is achieved with the highest priority as the low pressure adjustment is referred to as "low pressure control by the refrigerant (filling) amount adjustment means (RAAM)".

6) Target condensing temperature setting: preferably, the controller 224 refers to the outside air temperature (Ta) and sets the target condensation temperature (HP _ t) to be higher than the outside air temperature by a predetermined value (c1), as shown in equation 1.

Tc Ta + c1- - - (formula 1)

Example) c1 is 10.0, independent of load size, Tc is Ta +10.0

It is also preferable that the temperature of the outside air and the load are set with reference to the formula 2.

Tc Ta + c1+ c2 x Qc/Qc _ max- (formula 2)

Example) c 1-10.0, c 2-1.0, rated condensation load (Qc _ max) -10.0 kW,

if the condensation load (Qc) is 2kW, Tc is Ta +10.2 c,

if the condensation load (Qc) is 4kW, Tc is Ta +10.4 DEG C

7) Target evaporation temperature setting: preferably, the controller 224 refers to the default gas temperature (Tin) and sets the target evaporation temperature to be lower than the default gas temperature by a predetermined value (e1) as shown in equation 3.

Te is Tin-e1- - - (formula 3)

Example) e1 ═ 15.0, regardless of load size, and Te ═ Tin-15.0

It is also preferable to set the internal gas temperature (Tin) and the load size with reference to the equation 4.

Te ═ Tin- (e1+ e2 x Qe/Qe _ max) - - - (formula 4)

Example) e1 ═ 10.0, e2 ═ 10.0, and rated evaporation load (Qe _ max) ═ 10.0kW

If the evaporation load (Qe) is 3kW, Te is Tin-13.0 DEG C

If the evaporation load (Qe) is 9kW, Te is Tin-19.0 DEG C

On the other hand, it is needless to say that the target condensation temperature (HP _ t) and the target evaporation temperature (LP _ t) can be obtained by a plurality of prior experiments under various environments (for example, the outside air temperature, the internal set air temperature, the humidity, the set temperature, and the like), and the controller 224 can use the obtained values. The controller may set the target value (HP _ t) (LP _ t) at any time or at a predetermined control cycle, depending on the variation in load.

A preferred control sequence for raising the low pressure (keeping the high pressure constant) will be described with reference to the control sequence 100 of fig. 5. Since the low pressure is increased more than the present [ initial state (L0) ], the controller 224 sets the target low pressure (LP _ t) higher than the present (LP _ 0). Then, since the current low pressure (LP _0) is different from the target low pressure (LP _ t), the "low pressure control by the expansion valve" operation is performed so that the low pressure is equal to the target value (LP _ t), and the fourth control 4 is performed so that the expansion valve is opened further than the current one. By the fourth control 4, the high pressure is lowered and the low pressure is raised, and the state changes from (L0) to (L1). By means of said fourth control 4, the high pressure is disengaged from the target value (HP _ t). Then, in order to maintain the target high pressure (HP _ t), "high pressure control by the refrigerant (filling) amount adjusting means (RAAM)" is performed, and the first control 1 of filling the circuit with the refrigerant is performed. By the first control 1, both high pressure and low pressure rise, and the state changes from (L1) to (L2). As a result, the high pressure is maintained at the same value as the initial state (L0), and the low pressure is closer to the target low pressure (LP _ t). The states (L3) and (L4) illustrate the case where the fourth control 4 and the first control 1 are sequentially repeated 1 more times.

A preferred control sequence for lowering the low pressure (keeping the high pressure constant) will be described with reference to the control sequence 150 of fig. 5. Since the low pressure is reduced from the present [ initial state (L5) ], the controller 224 sets the target low pressure (LP _ t) lower than the present (LP _ 0). Then, since the current low pressure (LP _0) is different from the target low pressure (LP _ t), the "low pressure control by the expansion valve" operation is performed so that the low pressure is equal to the target value (LP _ t), and the third control 3 is performed so that the expansion valve is closed further than the current one. By the third control 3, the high pressure rises, the low pressure falls, and the state changes from (L5) to (L6). By means of said third control 3, the high pressure is disengaged from the target value (HP _ t). Then, in order to maintain the target high pressure (HP _ t), "high pressure control by the refrigerant (filling) amount adjusting means (RAAM)" is performed, and the second control 2 for recovering the refrigerant in the circuit is performed. By the second control 2, both high pressure and low pressure drop, and the state changes from (L6) to (L7). As a result, the high pressure is maintained at the same value as the initial state (L5), and the low pressure further approaches the target low pressure (LP _ t). The states (L8) and (L9) illustrate the case where the third control 3 and the second control 2 are sequentially repeated 1 more times.

The control sequences 200 and 250 can be described in a similar framework to the control sequences 100 and 150 described above, and thus a detailed description is omitted.

A preferred control sequence when the low pressure is to be increased (the high pressure is kept constant) will be described below with reference to the control sequence 101 of fig. 4. Since the low pressure is increased more than the present [ initial state (L0a) ], the controller 224 sets the target low pressure (LP _ t) higher than the present (LP _ 0). Then, since the current low pressure (LP _0) is different from the target low pressure (LP _ t), the "low pressure control by the refrigerant (filling) amount adjusting means (RAAM)" is operated so that the low pressure is equal to the target value (LP _ t), and the first control 1 of filling the refrigerant is performed. By the first control 1, both the high pressure and the low pressure rise, and the state changes from (L0a) to (L1 a). By the first control 1, the high pressure is deviated from the target value (HP _ t). Then, in order to maintain the target high pressure (HP _ t), the "high pressure control by the expansion valve" operation is performed to maintain the target high pressure (HP _ t), and the fourth control 4 for further opening the expansion valve is performed. By the fourth control 4, the high pressure is lowered and the low pressure is raised, and the state changes from (L1a) to (L2 a). As a result, the high pressure is maintained at the same value as the initial state (L0a), and the low pressure is closer to the target low pressure (LP _ t). The states (L3a) and (L4a) illustrate the case where the fourth control 4 and the first control 1 are sequentially repeated 1 more times.

If the control sequence 100 explained in the present embodiment is explained in a broad sense, it should be construed to include the control sequence 101. More specifically, the control sequences 100 and 101 both use the first control 1 for filling the refrigerant and the fourth control 4 for further closing the expansion valve. The low pressure is regulated in the control sequence 100 and the high pressure is regulated in the control sequence 101 by controlling the filling of the refrigerant. Also, by further closing the control of the expansion valve, the low pressure is regulated in the control sequence 100 and the high pressure is regulated in the control sequence 101. In short, even if the order of the first control 1 and the fourth control 4 is changed, the same result can be obtained. For this reason, the targets of the first control 1 and the fourth control 4 need to be changed from each other.

< example 4>

Referring to fig. 9, the preferred operation of the controller 224 on the major components in the cooling mode of the heat pump of the present invention is illustrated. The control sequence 100 to 250 of the present invention can be embodied by the case (a) in fig. 9. If explained in more detail, the controller 224 may perform the following first through seventh actions, running the control sequences 100 through 250.

1) Target condensing temperature (HP _ t) setting: the controller 224 functions to set a target temperature (target condensation temperature) at which the refrigerant boils inside the exterior heat exchanger (condenser) with reference to the outside air temperature, load, and the like. In the case where the outside air temperature and the load slowly rise as time goes from morning to midday, the target condensing temperature (HP _ t) may be slowly set higher than the present (HP).

2) Target evaporation temperature (LP _ t) setting: the controller 224 functions to set a target temperature (target evaporation temperature) at which the refrigerant boils inside the indoor heat exchanger (evaporator) with reference to the internal set gas temperature, the set temperature, and the like. When the difference between the inner-set gas temperature and the set temperature is small, and when the present evaporator fan (FN _ E) speed is below the design rating, the target evaporation temperature (LP _ t) can be set higher than now.

3) Controlling the compression amount of a refrigerant: the controller 224 controls the variable displacement compressor (C) so that a predetermined amount of refrigerant (g/s) is compressed per unit time. For example, if the low pressure and the degree of Superheat (SC) are kept at predetermined values, the amount of refrigerant (g/s) compressed by the compressor (C) per unit time is calculated as the compressor driving frequency because the density of the refrigerant is predetermined under the conditions [ fig. 9 (a) ].

4) Controlling the degree of superheat: the controller 224 functions to control the evaporator fan (FN _ E) speed so that the degree of Superheat (SH) becomes the target degree of superheat (SH _ t) [ intersection (a) of (SH _ t) and (FN _ E) in fig. 9 ].

5) Controlling the supercooling degree: the controller 224 controls the speed of the condenser fan (FN _ C) so that the supercooling degree (SC) becomes the target supercooling degree (SC _ t) [ intersection (a) of (SC _ t) and (FN _ C) in fig. 9 ].

6) Low-pressure control: the controller 224 controls the expansion valve (EXV) such that the Low Pressure (LP) becomes the target pressure (LP _ t). More specifically, if the expansion valve is adjusted, the high pressure is changed together with the low pressure. At this time, the controller performs a "low pressure control by the expansion valve" function of controlling so that the low pressure becomes a target value [ the intersection (a) of (LP _ t) and (EXV) in fig. 9 ].

7) High-pressure control: the controller 224 controls the refrigerant (filling) amount adjusting means (RAAM) so that the High Pressure (HP) becomes the target pressure (HP _ t). If the refrigerant is filled or recovered, the high pressure and the low pressure rise or fall at the same time. At this time, the controller performs a "high-pressure control by the refrigerant (filling) amount adjusting means (RAAM)" function of controlling the high pressure to a target value [ a cross point (a) between (HP _ t) and (RAAM) in fig. 9 ].

There is no particularly required order in which the controller 224 performs the first to seventh actions. As an extreme example, each component is provided with a controller, and each controller has an independent target, and control may be executed to achieve the target.

On the other hand, in order to execute the control sequence 100 to 250 of fig. 5, the pressure now needs to be different from the target pressure, and thus the first or second action of setting the target pressure needs to be run prior to the other actions. For example, the control sequence 100 sets the target evaporation temperature (LP _ t) higher than now (second action). Then, the low pressure is different from the target value, and thus "low pressure control by expansion valve" is automatically operated (sixth action). Then, the sixth action changes the high pressure, and the "high pressure control by the refrigerant (filling) amount adjusting means (RAAM)" automatically operates (seventh action).

The control sequence 150 is embodied with the second, sixth, and seventh functions as described above with reference to the control sequence 100. Only in the second action, the target evaporation temperature (LP _ t) is set lower than now, which is different from the control sequence 100.

The control sequences 200 and 250 first perform the first function of setting the target condensing temperature. Then, the high pressure is different from the target value, and thus "high pressure control by the refrigerant (filling) amount adjusting means (RAAM)" is automatically operated (seventh action). Then, the seventh action changes the low pressure, and the "low pressure control by the expansion valve" automatically operates (sixth action).

It has been described above that if the target high pressure or the target low pressure is set, the low pressure control (sixth action) and the high pressure control (seventh action) are automatically operated, and the control sequences 100 to 250 of the present invention are executed.

In embodiments 1 and 3, the same results were obtained by changing the control sequences 101 and 101 of the control targets of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM). If this is applied to case (a) of fig. 9, it becomes case (a'). More specifically, the controller adjusts the low pressure by the refrigerant (filling) amount adjusting means (RAAM) [ the intersection (a ') between (LP _ t) and (RAAM) in fig. 9 ], and adjusts the high pressure by the expansion valve [ the intersection (a ') between (HP _ t) and (EXV) in fig. 9, which will be simply referred to as "in fig. 9" hereinafter ], so that the state (a ') is reached.

In the cases (b) to (e) of fig. 9 described below, the first to third actions are the same as the case (a), and the fourth to seventh actions are different.

Fig. 9 (b) and (b') show the case where the fan speed is used to control all pressures (high pressure and low pressure) and the expansion valve and the refrigerant (filling amount) adjusting means are used to control the degree of superheat and the degree of supercooling. More specifically, the condenser fan (FN _ C) speed is controlled, the High Pressure (HP) [ (HP _ t) and (FN _ C) cross-over point (b) ] is adjusted, the evaporator fan (FN _ E) speed is controlled, and the Low Pressure (LP) [ (LP _ t) and (FN _ E) cross-over point (b) ] is adjusted. Then, the case (b) is assumed if the degree of Superheat (SH) [ (SH _ t) and (EXV) intersection (b) ] is adjusted by the expansion valve (EXV), and the degree of Supercooling (SC) [ (SC _ t) and (RAAM) intersection (b) ] is adjusted by the refrigerant (filling) amount adjusting means (RAAM).

In embodiments 1 and 3, the same results were obtained by changing the control sequences 101 and 101 of the control targets of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM). If it is applied to case (b) of fig. 9, it becomes case (b'). More specifically, in the case (b), if the control targets of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) are changed, the case (b') is reached. The case (b ') is assumed if the degree of Superheat (SH) [ (SH _ t) and (RAAM) intersection (b ') ] is adjusted by the refrigerant (filling) amount adjusting means (RAAM), and the degree of Supercooling (SC) [ (SC _ t) and (EXV) intersection (b ') ] is adjusted by the expansion valve (EXV).

The fans (evaporator fan, condenser fan) of the cases (a), (a '), (b) and (b') all control the pressure (high pressure, low pressure) or all adjust the temperature (degree of superheat, degree of supercooling).

Hereinafter, a case where the controller 224 controls the refrigerant (filling) amount adjusting means (RAAM) so that the High Pressure (HP) becomes the target high pressure (HP _ t) is referred to as x1, a case where the controller 224 controls the expansion valve (EXV) is referred to as x2, and a case where the controller 224 controls the speed of the condenser fan (FN _ C) is referred to as x 3.

When the controller 224 controls the refrigerant (filling) amount adjusting means (RAAM) so that the Low Pressure (LP) becomes the target low pressure (LP _ t), it is referred to as y1, when the controller 224 controls the expansion valve (EXV), it is referred to as y2, and when the controller 224 controls the speed of the evaporator fan (FN _ E), it is referred to as y 3.

If x1 to x3, which regulate the high pressure, is combined with y1 to y3, which regulate the low pressure, the high pressure and the low pressure can be regulated by the following 7 combinations. Namely, (x1, y2) (x1, y3) (x2, y1) (x2, y3) (x3, y1) (x3, y2) and (x3, y 3). As can be seen, the case a is the (x1, y2) combination, the case a' is the (x2, y1) combination, and the case b is the (x3, y3) combination.

On the other hand, in fig. 9, (d) and (e) are the cases where one of the two fans (evaporator fan, condenser fan) controls the pressure and the other controls the temperature of either the degree of superheat or the degree of supercooling.

More specifically, case (d) is combined by (x1, y3), controlling the evaporator fan (FN _ E) speed, adjusting the low pressure (y3) [ (LP _ t) and (FN _ E) cross-over point (d) ], controlling the expansion valve (EXV), adjusting the superheat degree (SH) [ (SH _ t) and (EXV) cross-over point (d) ]. And adjusting the High Pressure (HP) [ (HP _ t) and (RAAM) intersection (d) ] by controlling the amount of the refrigerant (filling) adjusting means (RAAM). Also, the condenser fan (FN _ C) speed is controlled to adjust the subcooling degree (SC) [ (SC _ t) and (FN _ C) cross point (d) ].

In the case (d), if the control targets of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) are changed, the case (d') is reached. More specifically, the expansion valve (EXV) is controlled to adjust the High Pressure (HP) [ (HP _ t) and (EXV) intersection (d ') ], the refrigerant (filling) amount adjusting means (RAAM) is controlled to adjust the superheat degree (SH) [ (SH _ t) and (RAAM) intersection (d') ]. As an example, if the degree of superheat is higher than the target, the refrigerant is filled by the above means to achieve the target degree of superheat (SH _ t). In the case (d'), the combination of (x2, y3) is known.

Case (E) is a combination of (x3, y2), controlling condenser fan (FN _ C) speed, adjusting High Pressure (HP) [ (HP _ t) and (FN _ C) intersection (E) ], controlling evaporator fan (FN _ E) speed, adjusting Superheat (SH) [ (SH _ t) and (FN _ E) intersection (E) ]. Controlling the expansion valve (EXV) and regulating the Low Pressure (LP) [ (LP _ t) and (EXV) intersection (e) ]. Furthermore, the supercooling degree (SC) [ (SC _ t) and (RAAM) intersection (e) ] is adjusted by controlling the amount of refrigerant (filling) adjusting means (RAAM).

In the case (e), if the control targets of the expansion valve (EXV) and the refrigerant (filling) amount adjusting means (RAAM) are changed to each other, the case (e') is reached. More specifically, the expansion valve (EXV) is controlled to adjust the supercooling degree (SC) [ (SC _ t) and (EXV) intersection (e ') ], the refrigerant (filling) amount adjusting means (RAAM) is controlled to adjust the Low Pressure (LP) [ (LP _ t) and (RAAM) intersection (e') ]. From these, it can be seen that the case (e') is a combination of (x3, y 1).

< Industrial effects >

The advantages of the present invention are briefly described below with reference to fig. 10. Fig. 10 refers to the (non-patent document) prior art mentioned in this specification, which is the result of measurement during 24 hours of starting the inverter air conditioner.

In fig. 10, the indoor load (IdLd) is represented by a quadrangle, the outside air temperature (OdT) is represented by a circle, and the indoor temperature (IdT) is represented by a dot. The power consumption (Pd) is indicated by a solid line. The room temperature (IdT) is suitably controlled to be between approximately 26 ℃ and 28 ℃. The outside air temperature (OdT) and the indoor load (ldld) slowly change with time from 0 to 24, and their forms are similar.

The measured power consumption (Pd) was repeatedly raised and lowered at a cycle of approximately 1.5 hours. The amplitude of the rise and fall is also about 1.5 kW. This is because the conventional art (for example, US2009/00137001 and KR 10-2016-. If the target pressure is achieved by other components (e.g., an expansion valve) or means (e.g., a refrigerant filling amount adjusting means) with low power consumption, the power consumption landing amplitude can be stabilized within several watts to several tens of watts. As a result, the power consumption of the heat pump also changes gradually in a manner (Pd2) similar to the indoor load (IdLd).

At this time, it is preferable that the compressor be controlled in conformity with the heat exchange required amount (IdLd). For example, if the compressor inlet pressure and the superheat degree are controlled to predetermined values, the refrigerant density at the compressor inlet is also fixed to a certain value. Therefore, if the refrigerant quantity corresponding to the heat exchange requirement (IdLd) is compressed (g/s) in unit time, the frequency of the inverter compressor is controlled. As shown in fig. 10, if the indoor load (IdLd) is slowly changed, the frequency of the inverter compressor is also slowly changed. The power consumption (Pd2) also changes slowly in a manner similar to the indoor load.

The present invention can eliminate the power fluctuation of several kW which appears at a time interval of approximately 1.5 hours in the conventional heat pump power consumption (Pd), and can reduce the reserve power of the power station. Further, the driving frequency of the compressor that actively generates the pressure is changed slowly, and thus the high pressure and the low pressure are also changed slowly, and thus the control procedure is simplified. As a result, higher-level optimization than ever before can be achieved, and improvement in energy efficiency is expected.

< example 5>

One example of setting the target condensing temperature (HP _ t) and the target evaporating temperature (LP _ t) in the cooling mode control of the heat pump suitable for the present invention is described below. The left side of fig. 11 is a table prepared with coefficients of performance (hereinafter referred to as "COP") with respect to a combination of the condensation temperature (Tc) and the evaporation temperature (Te). Also, the right side of fig. 11 is an example of calculating an energy consumption efficiency (hereinafter, referred to as "COP") during cooling using the COP.

First, in the COP table of fig. 11, the outside air temperature (Ta) is recorded from high value to low value at intervals of 1 ℃. In column (B), the condensing temperature (Tc) target value at the outside gas temperature (Ta) is recorded. The target condensing temperature (HP _ t) is set to be 10 ℃ higher than the external air temperature (Ta) using equation 1. In the column (D), COP calculated using the values in the column (B) is shown, with the evaporation temperature (Te) being 8 ℃ and the condensation temperature. (E) Columns (D) to (M) show COPs calculated in the same manner as in column (D). In the COP calculation, the evaporation temperature (Te) is a value between 8 ℃ and 17 ℃, and the condensation temperature (Tc) is a value in column (B).

A method of selecting the target evaporation temperature (LP _ t) will be explained below. In the COP table of fig. 11, a straight line is drawn from a point (hereinafter referred to as "first point") where the condensation temperature (Tc) is highest (53 ℃) and the evaporation temperature is lowest (8 ℃) to a point (hereinafter referred to as "second point") where the condensation temperature (Tc) is lowest (25 ℃) and the evaporation temperature is highest (17 ℃). The COP value (indicated by italic numbers) below the straight line is recorded in the (R) column and used for calculating CSPF. Then, the evaporation temperature (Te) of COP (indicated by italics) applied below the straight line is recorded in the column (C). (C) The evaporation temperature (Te) in the column is the target evaporation temperature (LP _ t) (hereinafter referred to as "evaporation temperature linear correction").

The following describes a method of calculating CSPF. In fig. 11, the CSPF calculation is calculated using the columns (N) to (R). The outside air temperature (Ta) is recorded in column (N). The COP of the heat pump at the outside air temperature (Ta) (italic numbers below the straight line in fig. 11) is recorded in the column (R). Columns (O) to (Q) fill out air conditioner start-up times with respect to the outside air temperatures of the respective regions. The column (O) is Indian, the column (P) is Korea, and the column (Q) is ISO 16358 value. If the CSPF is calculated using the air conditioner start time of the column, india is 6.33, korea is 6.98, ISO 16358 is 7.60.

In the above method, the lower the outside air temperature is, the higher the target evaporation temperature is set. This is generally the lower the outside air temperature, the lower the refrigeration load. At this time, the heat exchange amount is calculated using Q as c · m · dT, thereby making Q satisfy the load. More specifically, dT is decreased, the power consumption of the compressor that consumes the most power in the heat pump is decreased, and m is increased so that Q is the same as before dT is decreased. However, lowering dT may raise the refrigerant evaporation temperature (i.e., raise the low pressure) and reduce the temperature difference with the air flowing into the heat exchanger.

The following describes a method for further improving CSPF. In the COP table of fig. 12, in the vicinity of the second point (i.e., the evaporation temperature of 17 ℃ and the condensation temperature of 25 to 31 ℃), a COP having a higher value than the COP below the line connecting the two points is selected as the target COP. Also, the evaporation temperature (Te) at which the target COP is calculated is taken as a target evaporation temperature (LP _ t). Also, the target COP is used for CSPF calculation. As a specific numerical value, for example, when the outside air temperature (Ta) is 28 ℃, the COP under the line is 6.50. Among the COP values above said value, 7.14 (below the curve) is chosen. Further, the evaporation temperature (Te) for calculating the COP is selected to be 15 ℃ as the target evaporation temperature (LP _ t). Since the COP selected in the curve near the second location is higher than the COP selected on the straight line, and the air-conditioning start-up time is relatively long, CSPF is significantly improved over the conventional case (hereinafter referred to as "correction of the evaporation temperature curve on the low outdoor air side").

If an example of COP to be selected by the above description is visually expressed, it may be exemplified as shown by a curve indicated by a dotted line in fig. 12. In fig. 12, if the COP value (indicated by italic numbers) below the curve is used to calculate CSPF, the improvement is made over when the COP value below the straight line is used. That is, india changes from 6.33 to 6.82, korea changes from 6.98 to 7.68, ISO 16358 changes from 7.60 to 8.40, and CSPF improves. At this time, the "evaporation temperature curve correction on the low side of the outside air" is shown on the right side of the straight line (connecting the first point and the second point) in the table of fig. 12.

In this embodiment, CSPFs for a plurality of regions are calculated using a set of target COP values displayed in the (R) column. In a practical implementation, CSPF may be calculated using a target condensing temperature (HP _ t) and a target evaporating temperature (LP _ t) optimized for each region. In other words, the target evaporation temperature can be selected by regarding the maximum temperature and the minimum temperature of the outside air for calculating the CSPF for each region as the first point and the second point. Therefore, the minimum and maximum values of the condensation temperature and the evaporation temperature may vary from region to region.

On the other hand, the concept of the present embodiment may be applied to the integrated refrigeration efficiency (IEER) calculated by obtaining the coefficient of performance of each load from several loads (for example, 100%, 75%, 50%, and 25% loads) and giving a weighted value in consideration of the load activation time.

The foregoing describes preferred embodiments of the present invention.

In the present invention, the case where the heat pump is operated in the cooling mode is described in detail, but it is needless to say that the concept of the present invention can be applied to the heating mode. Although the description is made with respect to one compressor, one outdoor heat exchanger (HEX _ EX), and one indoor heat exchanger (HEX _ IN), it is obvious to a person skilled IN the art that the present invention may be embodied with a plurality of heat exchangers and a plurality of compressors. It is needless to say that the concept and the control method of the invention can be applied to the heat pump circuit exemplified in the prior art document.

In the present specification, the case of heat exchange with air is described, but it is needless to say that the practitioner may exchange heat with liquid. Thus, in the present invention, air is to be interpreted as a "fluid" comprising water. At this time, the fan supplying the fluid to the heat exchanger of course includes a pump for flowing the liquid in the heat exchanger.

While the present invention has been described with reference to preferred embodiments thereof, it is to be understood that the present invention is merely illustrative and that various modifications may be made by those skilled in the art. Therefore, the embodiments of the present invention disclosed in the specification and the drawings are only intended to easily explain the technical contents of the present invention and to assist understanding of the present invention to provide specific examples, and are not intended to limit the scope of the present invention.

[ Industrial Applicability ]

The heat pump of the present invention can minimize the high pressure and low pressure difference while maintaining the heat exchange amount, and improve the energy efficiency, and thus the industrial applicability is very high. More specifically, in the heat pump, if the difference between the inlet pressure and the outlet pressure of the compressor, which consumes the most power, is increased, the compressor consumes more power even if it is started at the same frequency. According to the present invention, the inlet pressure and the outlet pressure of the compressor are controlled to achieve the highest priority, and a heat pump having improved efficiency compared to the conventional heat pump is provided, and thus the present invention has high industrial applicability.

Further, according to the present invention, it is possible to eliminate power fluctuation of several kW, which occurs at a time interval of approximately 1.5 hours in a conventional heat pump, and to reduce the reserve power of the power plant. Further, since the driving frequency of the compressor that actively generates the pressure is changed slowly, the high pressure and the low pressure are also changed slowly, and thus the control procedure is simplified. As a result, it is possible to achieve higher-level optimization than before, and a heat pump having improved efficiency than before is provided, and therefore, the industrial applicability is high.