阅读说明：本技术 土壤温度恢复装置及方法 (Soil temperature recovery device and method ) 是由 李永 刘士龙 刘建林 李沫 张宁 朱静 于 2020-05-12 设计创作，主要内容包括：本发明公开了一种土壤温度恢复装置及方法,属于供热技术领域,包括表冷器、热泵机组及地埋管换热器,多个采暖末端出口与水管I并联,水管I通过水泵I、热泵机组及水管VII与地埋管换热器进口相连,地埋管换热器出口与水管VIII相连,水管VIII上设有水泵II,水泵II出口通过热泵机组与水管II相连,水管II与若干个采暖末端进口并联；表冷器出口并联水管IV及水管V,水管IV另一端与水泵I进口相连,水管V另一端与地埋管换热器进口相连,表冷器进口并联水管III及水管VI,水管III另一端与水管II相连,水管VI另一端与水泵II出口相连,各水管上均设有阀门。利用本发明能够实现对土壤的补热,进而提升土壤温度。本发明尤其适用于单供暖的大规模居住建筑。(The invention discloses a soil temperature recovery device and a method, belonging to the technical field of heat supply, and comprising a surface air cooler, a heat pump unit and a ground heat exchanger, wherein a plurality of heating tail end outlets are connected in parallel with a water pipe I, the water pipe I is connected with the inlet of the ground heat exchanger through a water pump I, the heat pump unit and a water pipe VII, the outlet of the ground heat exchanger is connected with a water pipe VIII, a water pump II is arranged on the water pipe VIII, the outlet of the water pump II is connected with the water pipe II through the heat pump unit, and the water pipe II is connected with a plurality of heating tail end; parallelly connected water pipe IV of surface cooler export and water pipe V, the water pipe IV other end links to each other with water pump I import, and the water pipe V other end links to each other with the ground heat exchanger import, and parallelly connected water pipe III of surface cooler import and water pipe VI, the water pipe III other end links to each other with water pipe II, and the water pipe VI other end links to each other with water pump II export, all is equipped with the valve on each water pipe. The invention can realize heat supplement to the soil, thereby improving the soil temperature. The invention is especially suitable for large-scale residential buildings with single heating.)

1. A soil temperature recovery device is characterized by comprising a surface air cooler, a heat pump unit, a ground heat exchanger and a plurality of heating terminals, wherein water outlets of the heating terminals are connected with a water pipe I in parallel, the water pipe I is connected with an inlet of the ground heat exchanger sequentially through a water pump I, the heat pump unit and a water pipe VII, a water outlet of the ground heat exchanger is connected with a water pipe VIII, a water pump II is arranged on the water pipe VIII, an outlet of the water pump II is connected with the water pipe II through the heat pump unit, and the water pipe II is connected with water inlets of the heating terminals in parallel; the outlet of the surface air cooler is connected with a water pipe IV and a water pipe V in parallel, the other end of the water pipe IV is connected with the inlet of a water pump I, the other end of the water pipe V is connected with the inlet of the buried pipe heat exchanger, the inlet of the surface air cooler is connected with a water pipe III and a water pipe VI in parallel, the other end of the water pipe III is connected with a water pipe II, and the other end of the water pipe VI is connected with the outlet of the water pump II;

be equipped with valve I on water pipe I, and valve I sets up between water pipe IV and heating end, be equipped with valve II on water pipe II, and valve II sets up between heat pump set and heating end, be equipped with valve III on water pipe III, be equipped with valve IV on the water pipe IV, be equipped with valve V on the water pipe V, be equipped with valve VI on the water pipe VI, be equipped with valve VII on the water pipe VII, valve VII sets up between water pipe V and heat pump set, be equipped with valve VIII on the water pipe VIII, valve VIII sets up between water pump II and heat pump set.

2. The soil temperature recovery device of claim 1, wherein: the surface cooler, the heat pump unit, the water pump I and the water pump II are all electrically connected with the controller.

3. The soil temperature recovery device of claim 2, wherein: the valves I to VIII are all electromagnetic valves which are all electrically connected with the controller.

4. A soil temperature restoration method, characterized in that the soil temperature restoration using the soil temperature restoration device according to claim 2 or 3 is performed as follows:

1) normal heat supply: the main machine of the heat pump unit is started, the water pump I and the water pump II are started, the valve III, the valve IV, the valve V and the valve VI are closed, and the valve I, the valve II, the valve VII and the valve VIII are opened;

2) active heat supplement: the heat pump set host is started, the water pump I and the water pump II are started, the valve I, the valve II, the valve V and the valve VI are closed, and the valve III, the valve IV, the valve VII and the valve VIII are opened; starting a heat pump unit for heating, absorbing heat from outdoor air by an evaporator of the heat pump unit through a surface air cooler, and storing the heat discharged by a condenser of the heat pump unit into underground soil by using a ground heat exchanger to play a role in recovering the ground temperature;

3) passive heat supplement: the heat pump host is closed, the water pump I and the water pump II are opened, the valve I, the valve II, the valve III, the valve IV, the valve VII and the valve VIII are closed, and the valve V and the valve VI are opened; the heat pump unit is not started, the surface cooler is utilized to directly absorb heat from outdoor air, and then the heat in the air is stored in underground soil through the buried pipe heat exchanger;

4) switching between active heat compensation and passive heat compensation:

firstly, active heat compensation is adopted, the soil temperature increase value is used as an independent variable, the soil increase temperature when the sum of the heat compensation and heating cost is the lowest value is used as a target increase temperature, and when the target increase temperature is close to the soil temperature decrease value caused by annual heating heat, the soil temperature decrease value is converted into passive heat compensation.

5. The soil temperature recovery method of claim 4, wherein the soil temperature recovery device is controlled by the controller, and the surface cooler is selected and supplemented with heat as follows:

A. selecting the surface air cooler according to the passive heat supplementing working condition, and checking and calculating the surface air cooler as follows:

recall local chronological meteorological data including air dry bulb temperature t_kWet bulb temperature t_s1And enthalpy value i₁Inputting the dry air ball temperature t of the heat-supplementing equipment during starting operation into a checking calculation formula of the surface cooler_kWet bulb temperature t_s1And enthalpy value i₁Initial temperature t of soil_sAnd building cumulative heat load Q, the initial temperature t of the soil_sAs the inlet water temperature of the surface cooler and the indoor circulating water quantity W₂Using local time-by-time meteorological data and a method for checking and calculating the surface cooler, and continuously adjusting the temperature t of the air dry bulb when the heat-compensating equipment is started to operate_kWet bulb temperature t_s1Enthalpy value i₁And the model of the surface cooler to be selected, when the selected surface cooler can meet the target total heat exchange quantity under the parameter limiting conditions, the surface cooler can be selected, and meanwhile, the air dry bulb temperature t of the heat-compensating equipment under the passive heat-compensating working condition during starting operation is controlled_kWet bulb temperature t_s1And enthalpy value i₁Is also determined;

air dry bulb temperature t in check calculation of surface cooler_kFirstly, inputting: initial temperature t of soil_s+10 ℃; wet bulb temperature t_s1And enthalpy value i₁The temperature t of the air dry bulb in the chronological meteorological data is taken_kThe value at the same time;

B. checking whether the area of the surface cooler meets the requirement of the active heat supplement working condition or not, wherein the checking method comprises the following steps:

under the working condition of active heat compensation, the water inlet temperature of the surface air cooler is set to be 7 +/-3 ℃, the water inlet temperature of the side inlet of the buried pipe is 25 +/-3 ℃, the water inlet temperature of the surface air cooler is lower than that of the surface air cooler under the working condition of passive heat compensation, and the required heat exchange amount is larger than that under the working condition of passive heat compensation; verifying whether the selected surface air cooler can meet the requirement of heat extraction of an evaporator of a heat pump unit under the conditions of dry bulb temperature, wet bulb temperature and enthalpy value of air when the heat supplementing equipment is started to operate; if the requirement is not met, increasing the model of the surface cooler until the requirement is met; if the requirement is met, selecting the surface cooler, and entering the next step;

C. calculating the annual target lifting temperature of the soil under the active heat supplementing working condition; the calculation period is 10 years and is used for allocating the initial investment generated by additionally arranging the surface cooler, and the calculation mode is as follows:

during calculation, the lifting value delta t of the soil temperature is taken as an independent variable, and the total cost C of heat supply and heating is obtained_ztAs a dependent variable, the soil lifting temperature when the sum of the heat supplement cost and the heating cost is minimum is taken as a target lifting temperature;

C_zt＝C_bt/n+C_qt+1.1×C_bx+1.1×C_zx(1)

C_bx＝p×ρ_sc_sV×(t_s0+Δt)/COP_b+p×(P_sw+P_sn+P_b) (2)

C_bx＝p×Q×(COP_i-1)/COP_i+p×(P_sw+P_sn) (3)

in the formula (1), C_ztThe total annual heat supply and heating cost is Yuan; c_btThe method is the initial investment of the surface cooler; c_qtInvestment for other parts of the system; c_bxAnnual operation cost of a system in a heat supply period is guaranteed; c_zxAnnual operating cost, yuan/year, for the heating period of the system; and n is the operation life of the system, and 10 years are taken.

In the formulae (2) and (3), ρ_sc_sIs the specific heat capacity of soil, J/(m)³DEG C.) and V is the volume (the hole number is × intervals) of the arrangement of the buried pipe heat exchange system²× buried depth), m³；t_s0In the current situation of soilTemperature, deg.C; delta t is the soil lifting temperature, DEG C; p is the local electricity price, yuan/kWh; COP_bEfficiency of heat pump set in heat supplementing condition (its magnitude depends on t)_s0，t_s0The smaller, the COP_bLarger), dimensionless; COP_iEfficiency of heat pump unit in heating condition (its magnitude depends on t)_s0+Δt，t_s0The smaller the + Δ t, the COP_iLarger), dimensionless; p_swThe power consumption of the outdoor water pump is kWh; p_snThe power consumption of the indoor water pump is kWh; p_bThe power consumption of the surface cooler is kWh.

D. Repeating the step C to complete the design calculation of other years needing active heat supplement according to the t of the year_s0+ Δ t as t for the next year_s0) (ii) a When the target soil temperature rise value is close to the soil temperature drop value caused by winter heating, the active heat supplement is not started, the operation mode is switched, and all the operation in the later period is passive heat supplement;

E. and outputting a result: the results include specific parameters of the surface air cooler, dry bulb temperature, wet bulb temperature and enthalpy of the air when the heat recovery device is started, target annual rise temperatures, and the sum of the heat recovery and heating costs.

F. And inputting the dry bulb temperature, the wet bulb temperature, the enthalpy value and the annual target rise temperature of the air when the heat supplementing equipment is started into a controller to control the operation of the system.

Technical Field

The invention belongs to the technical field of heat supply, and particularly relates to a soil temperature recovery device and method.

Background

In recent years, a buried pipe ground source heat pump is widely popularized and applied as a form of renewable energy building application. However, due to the reasons that the technology is not completely known and is subjected to extensive commercial stir-frying, the technology is adopted by many projects which are not suitable for adopting the technology, and a plurality of problems are caused in the operation process of the system. The most typical problem is that in a large-scale residential building with single heating, the soil temperature tends to decrease year by year, and after a plurality of projects run for several years, the soil temperature decreases year by year, and finally the soil temperature is too low to continue normal heating, so that the heating cost is higher and higher. Therefore, finding a technology which can raise and recover the soil temperature at an acceptable cost as soon as possible has become a problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a soil temperature recovery device and a soil temperature recovery method, and aims to solve the technical problem that continuous and stable heating cannot be guaranteed due to the fact that the soil temperature is reduced in the prior art.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a soil temperature recovery device comprises a surface air cooler, a heat pump unit, a ground heat exchanger and a plurality of heating terminals, wherein water outlets of the heating terminals are connected in parallel with a water pipe I, the water pipe I is connected with an inlet of the ground heat exchanger sequentially through a water pump I, the heat pump unit and a water pipe VII, a water outlet of the ground heat exchanger is connected with a water pipe VIII, a water pump II is arranged on the water pipe VIII, an outlet of the water pump II is connected with the water pipe II through the heat pump unit, and the water pipe II is connected in parallel with water inlets of the heating terminals; the outlet of the surface air cooler is connected with a water pipe IV and a water pipe V in parallel, the other end of the water pipe IV is connected with the inlet of a water pump I, the other end of the water pipe V is connected with the inlet of the buried pipe heat exchanger, the inlet of the surface air cooler is connected with a water pipe III and a water pipe VI in parallel, the other end of the water pipe III is connected with a water pipe II, and the other end of the water pipe VI is connected with the outlet of the water pump II;

be equipped with valve I on water pipe I, and valve I sets up between water pipe IV and heating end, be equipped with valve II on water pipe II, and valve II sets up between heat pump set and heating end, be equipped with valve III on water pipe III, be equipped with valve IV on the water pipe IV, be equipped with valve V on the water pipe V, be equipped with valve VI on the water pipe VI, be equipped with valve VII on the water pipe VII, valve VII sets up between water pipe V and heat pump set, be equipped with valve VIII on the water pipe VIII, valve VIII sets up between water pump II and heat pump set.

Preferably, the surface air cooler, the heat pump unit, the water pump I and the water pump II are all electrically connected with the controller.

Preferably, the valves I to VIII are all electromagnetic valves, and the electromagnetic valves are all electrically connected with the controller.

The invention also provides a soil temperature recovery method, and the operation process of the soil temperature recovery by applying the soil temperature recovery device is as follows:

1) normal heat supply: the main machine of the heat pump unit is started, the water pump I and the water pump II are started, the valve III, the valve IV, the valve V and the valve VI are closed, and the valve I, the valve II, the valve VII and the valve VIII are opened;

2) active heat supplement: the heat pump set host is started, the water pump I and the water pump II are started, the valve I, the valve II, the valve V and the valve VI are closed, and the valve III, the valve IV, the valve VII and the valve VIII are opened; starting a heat pump unit for heating, absorbing heat from outdoor air by an evaporator of the heat pump unit through a surface air cooler, and storing the heat discharged by a condenser of the heat pump unit into underground soil by using a ground heat exchanger to play a role in recovering the ground temperature;

3) passive heat supplement: the heat pump host is closed, the water pump I and the water pump II are opened, the valve I, the valve II, the valve III, the valve IV, the valve VII and the valve VIII are closed, and the valve V and the valve VI are opened; the heat pump unit is not started, the surface cooler is utilized to directly absorb heat from outdoor air, and then the heat in the air is stored in underground soil through the buried pipe heat exchanger;

4) switching between active heat compensation and passive heat compensation:

firstly, active heat compensation is adopted, the soil temperature increase value is used as an independent variable, the soil increase temperature when the sum of the heat compensation and heating cost is the lowest value is used as a target increase temperature, and when the target increase temperature is close to the soil temperature decrease value caused by annual heating heat, the soil temperature decrease value is converted into passive heat compensation.

Preferably, the soil temperature recovery device is controlled by the controller, and the selection and the heat supplementing process of the surface cooler are as follows:

A. selecting the surface air cooler according to the passive heat supplementing working condition, and checking and calculating the surface air cooler as follows:

recall local chronological meteorological data including air dry bulb temperature t_kWet bulb temperature t_s1And enthalpy value i₁Inputting the dry air ball temperature t of the heat-supplementing equipment during starting operation into a checking calculation formula of the surface cooler_kWet bulb temperature t_s1And enthalpy value i₁Initial temperature t of soil_sAnd building cumulative heat load Q, the initial temperature t of the soil_sAs the inlet water temperature of the surface cooler and the indoor circulating water quantity W₂Using local time-by-time meteorological data and a method for checking and calculating the surface cooler, and continuously adjusting the temperature t of the air dry bulb when the heat-compensating equipment is started to operate_kWet bulb temperature t_s1Enthalpy value i₁And the model of the surface cooler to be selected, when the selected surface cooler can meet the target total heat exchange quantity under the parameter limiting conditions, the surface cooler can be selected, and meanwhile, the air dry bulb temperature t of the heat-compensating equipment under the passive heat-compensating working condition during starting operation is controlled_kWet bulb temperature t_s1And enthalpy value i₁Is also determined;

air dry bulb temperature t in check calculation of surface cooler_kFirstly, inputting: initial temperature t of soil_s+10 ℃; wet bulb temperature t_s1And enthalpy value i₁The temperature t of the air dry bulb in the chronological meteorological data is taken_kThe value at the same time;

B. checking whether the area of the surface cooler meets the requirement of the active heat supplement working condition or not, wherein the checking method comprises the following steps:

under the working condition of active heat compensation, the water inlet temperature of the surface air cooler is set to be 7 +/-3 ℃, the water inlet temperature of the side inlet of the buried pipe is 25 +/-3 ℃, the water inlet temperature of the surface air cooler is lower than that of the surface air cooler under the working condition of passive heat compensation, and the required heat exchange amount is larger than that under the working condition of passive heat compensation; verifying whether the selected surface air cooler can meet the requirement of heat extraction of an evaporator of a heat pump unit under the conditions of dry bulb temperature, wet bulb temperature and enthalpy value of air when the heat supplementing equipment is started to operate; if the requirement is not met, increasing the model of the surface cooler until the requirement is met; if the requirement is met, selecting the surface cooler, and entering the next step;

C. calculating the annual target lifting temperature of the soil under the active heat supplementing working condition; the calculation period is 10 years and is used for allocating the initial investment generated by additionally arranging the surface cooler, and the calculation mode is as follows:

during calculation, the lifting value delta t of the soil temperature is taken as an independent variable, and the total cost C of heat supply and heating is obtained_ztAs a dependent variable, the soil lifting temperature when the sum of the heat supplement cost and the heating cost is minimum is taken as a target lifting temperature;

C_zt＝C_bt/n+C_qt+1.1×C_bx+1.1×C_zx(1)

C_bx＝p×ρ_sc_sV×(t_s0+Δt)/COP_b+p×(P_sw+P_sn+P_b) (2)

C_bx＝p×Q×(COP_i-1)/COP_i+p×(P_sw+P_sn) (3)

in the formula (1), C_ztThe total annual heat supply and heating cost is Yuan; c_btThe method is the initial investment of the surface cooler; c_qtInvestment for other parts of the system; c_bxAnnual operation cost of a system in a heat supply period is guaranteed; c_zxAnnual operating cost, yuan/year, for the heating period of the system; and n is the operation life of the system, and 10 years are taken.

In the formulae (2) and (3), ρ_sc_sIs the specific heat capacity of soil, J/(m)³DEG C.) and V is the volume (the hole number is × intervals) of the arrangement of the buried pipe heat exchange system²× buried depth), m³；t_s0At the present soil temperature, DEG C; delta t is the soil lifting temperature, DEG C; p is the local electricity price, yuan/kWh; COP_bEfficiency of heat pump set in heat supplementing condition (its magnitude depends on t)_s0，t_s0The smaller, the COP_bLarger), dimensionless; COP_iEfficiency of heat pump unit in heating condition (its magnitude depends on t)_s0+Δt，t_s0The smaller the + Δ t, the COP_iLarger), dimensionless; p_swThe power consumption of the outdoor water pump is kWh; p_snThe power consumption of the indoor water pump is kWh; p_bThe power consumption of the surface cooler is kWh.

D. Repeating the step C to complete the design calculation of other years needing active heat supplement according to the t of the year_s0+ Δ t as t for the next year_s0) (ii) a When the target soil temperature rise value is close to the soil temperature drop value caused by winter heating, the active heat supplement is not started, the operation mode is switched, and all the operation in the later period is passive heat supplement;

E. and outputting a result: the results include specific parameters of the surface air cooler, dry bulb temperature, wet bulb temperature and enthalpy of the air when the heat recovery device is started, target annual rise temperatures, and the sum of the heat recovery and heating costs.

F. And inputting the dry bulb temperature, the wet bulb temperature, the enthalpy value and the annual target rise temperature of the air when the heat supplementing equipment is started into a controller to control the operation of the system.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: compared with the prior art, the invention greatly reduces the initial investment compared with solar energy heat compensation and air source heat pump heat compensation, the efficiency of the heat compensation working condition is much higher than that of the heating working condition when the heat is actively compensated, the evaporator of the heat pump unit absorbs heat from outdoor air through the surface air cooler, and then the heat in the air is stored in underground soil through the buried pipe heat exchanger, thereby achieving the purpose of improving the soil temperature. During passive concurrent heating, do not open heat pump set, utilize the surface cooler directly to absorb the heat from outdoor air, then through the buried pipe heat exchanger with the heat in the air in the storage underground soil, play the effect of recovering soil temperature. The invention is particularly suitable for large-scale residential buildings which adopt the soil source heat pump for single heating and have obvious reduction of soil temperature after running for years, and ensures the long-term stable heating of the buried pipe ground source heat pump.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic structural diagram of a soil temperature recovery device according to an embodiment of the present invention;

FIG. 2 is a graph of soil temperature versus cost in accordance with the present invention;

FIG. 3 is a design flow diagram of the present invention;

in the figure: 00-ground heat exchanger; 001-pump I, 002-pump II; 01-water pipe I, 02-water pipe II, 03-water pipe III, 04-water pipe IV, 05-water pipe V, 06-water pipe VI, 07-water pipe VII, 08-water pipe VIII; 11-valve I, 12-valve II, 13-valve III, 14-valve IV, 15-valve V, 16-valve VI, 17-valve VII, 18-valve VIII.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The soil is an energy storage body with large heat capacity, the soil temperature tends to decrease year by year in large-scale residential buildings with single heating in cold regions, and after a plurality of projects run for a plurality of years, the soil temperature decreases year by year, and finally the soil temperature is low enough to prevent normal heating, so that the heating cost is higher and higher. The main measure for solving the soil heat balance is to adopt a cross-season heat storage solar energy-soil composite heat pump system, and the system stores solar energy in soil for taking out in heating seasons. On one hand, however, the cost of the current solar heat collector is relatively high, so that the engineering application of the solar heat collector is limited; on the other hand, large residential quarters do not have sufficient space to arrange solar collectors.

The average temperature of soil in northern China is lower, the non-heating period is longer, and the environmental temperature in most of the non-heating period is higher than the temperature of soil heated in winter, so that the temperature of the soil can be increased if the heat energy stored in outdoor air can be stored in the soil by adopting a scientific and reasonable means. Based on the method, a large-scale buried pipe heat exchange system soil temperature recovery method combining active and passive is provided.

As shown in fig. 1, the soil temperature recovery device provided by the invention comprises a surface air cooler, a heat pump unit, a ground heat exchanger and a plurality of indoor heating modules, wherein water outlets of the plurality of indoor heating modules are connected in parallel with a water pipe I01, the water pipe I01 is connected with an inlet of the ground heat exchanger sequentially through a water pump I001, the heat pump unit and a water pipe VII 007, a water outlet of the ground heat exchanger is connected with a water pipe VIII08, a water pump II002 is arranged on the water pipe VIII08, an outlet of the water pump II002 is connected with a water pipe II02 through the heat pump unit, and a water pipe II02 is connected in parallel with water inlets of the plurality of indoor heating modules; the outlet of the surface air cooler is connected with a water pipe IV04 and a water pipe V05 in parallel, the other end of the water pipe IV04 is connected with the inlet of a water pump I001, the other end of the water pipe V05 is connected with the inlet of the ground heat exchanger, the inlet of the surface air cooler is connected with a water pipe III03 and a water pipe VI06 in parallel, the other end of the water pipe III03 is connected with a water pipe II02, and the other end of the water pipe VI06 is connected with the outlet of a water pump II 002;

be equipped with valve I11 on water pipe I01, and valve I11 sets up between water pipe IV14 and indoor heating module, be equipped with valve II12 on water pipe II02, and valve II12 sets up between heat pump set and indoor heating module, be equipped with valve III13 on water pipe III03, be equipped with valve IV14 on water pipe IV04, be equipped with valve V15 on water pipe V05, be equipped with valve VI16 on water pipe VI06, be equipped with valve VII17 on water pipe VII07, valve VII17 sets up between water pipe V05 and heat pump set, be equipped with valve VIII18 on water pipe VIII08, valve VIII18 sets up between water pump II002 and heat pump set. The surface cooler is a surface type air cooler, and heat in outdoor air can be conducted to soil through the structure, so that heat compensation and heating can be performed on low-temperature soil.

As a preferred scheme, the surface air cooler, the heat pump unit, the water pump I and the water pump II are electrically connected with the controller, and the soil temperature recovery device is controlled by the controller. In order to control each valve conveniently, the valves I to VIII all adopt electromagnetic valves which are all electrically connected with a controller. By adopting the structure, the automatic control of the equipment can be realized.

The invention also provides a soil temperature recovery method, and the operation process of the soil temperature recovery by applying the soil temperature recovery device is as follows:

1) normal heat supply: the main machine of the heat pump unit is started, the water pump I and the water pump II are started, the valve III, the valve IV, the valve V and the valve VI are closed, and the valve I, the valve II, the valve VII and the valve VIII are opened;

2) active heat supplement: the heat pump set host is started, the water pump I and the water pump II are started, the valve I, the valve II, the valve V and the valve VI are closed, and the valve III, the valve IV, the valve VII and the valve VIII are opened; starting a heat pump unit for heating, absorbing heat from outdoor air by an evaporator of the heat pump unit through a surface air cooler, and storing the heat discharged by a condenser of the heat pump unit into underground soil by using a ground heat exchanger to play a role in recovering the ground temperature;

3) passive heat supplement: the heat pump host is closed, the water pump I and the water pump II are opened, the valve I, the valve II, the valve III, the valve IV, the valve VII and the valve VIII are closed, and the valve V and the valve VI are opened; the heat pump unit is not started, the surface cooler is utilized to directly absorb heat from outdoor air, and then the heat in the air is stored in underground soil through the buried pipe heat exchanger;

4) switching between active heat compensation and passive heat compensation:

in the initial stage of heat supplement, an active heat supplement strategy is needed, and because the temperature of soil is reduced very low, the heat supplement quantity is insufficient to meet the requirement of efficient and stable heating in the later stage by passive heat supplement. The method is characterized in that the lifting value of the soil temperature is used as an independent variable, the temperature when the sum of the heat supplement cost and the heating cost is the lowest is used as a target lifting temperature, when the target lifting temperature is close to the soil temperature reduction value caused by annual heating heat, the target lifting temperature is converted into passive heat supplement, and the soil temperature reaches the balance temperature. An exact soil temperature increase target value is provided every year, and when the soil temperature decrease value caused by the soil target increase temperature and the annual heating heat is close to each other, passive heat supplement is converted. The soil temperature at this time is called "equilibrium temperature", and the magnitude of the equilibrium temperature depends on the efficiency of the heat pump system, local outdoor meteorological parameters, electricity prices, and the like.

The soil temperature recovery device is controlled by a controller, the design flow is shown in figure 3,

the selection process of the surface cooler under the working conditions of active heat compensation and passive heat compensation is as follows:

A. selecting the surface air cooler according to the passive heat supplementing working condition, and checking and calculating the surface air cooler as follows:

recall local chronological meteorological data including air dry bulb temperature t_kWet bulb temperature t_s1And enthalpy value i₁Inputting the dry air ball temperature t of the heat-supplementing equipment during starting operation into a checking calculation formula of the surface cooler_kWet bulb temperature t_s1And enthalpy value i₁Initial temperature t of soil_sAnd building cumulative heat load Q, the initial temperature t of the soil_sAs the inlet water temperature of the surface cooler and the indoor circulating water quantity W₂Using local time-by-time meteorological data and a method for checking and calculating the surface cooler, and continuously adjusting the temperature t of the air dry bulb when the heat-compensating equipment is started to operate_kWet bulb temperature t_s1Enthalpy value i₁And the model of the surface cooler to be selected, when the selected surface cooler can meet the target total heat exchange quantity under the parameter limiting conditions, the surface cooler can be selected, and meanwhile, the air dry bulb temperature t of the heat-compensating equipment under the passive heat-compensating working condition during starting operation is controlled_kWet bulb temperature t_s1And enthalpy value i₁Is also determined;

air dry bulb temperature t in check calculation of surface cooler_kFirstly, inputting: initial temperature t of soil_s+10 ℃; wet bulb temperature t_s1And enthalpy value i₁Taking chronological meteorological data to neutralizeAir dry bulb temperature t_kThe value at the same time.

The calibration and calculation method of the surface cooler is explained in detail in pages 145-160 of the principle and apparatus for heat and mass exchange (master edition: Lianweiwei). And determining the model of the surface cooler under the passive heat supplementing working condition through checking calculation of the surface cooler.

B. Checking whether the area of the surface cooler meets the requirement of the active heat supplement working condition or not, wherein the checking method comprises the following steps:

under the working condition of active heat compensation, the water inlet temperature of the surface air cooler is set to be 7 +/-3 ℃, the water inlet temperature of the side inlet of the buried pipe is 25 +/-3 ℃, the water inlet temperature of the surface air cooler is lower than that of the surface air cooler under the working condition of passive heat compensation, and the required heat exchange amount is larger than that under the working condition of passive heat compensation; verifying whether the selected surface air cooler can meet the requirement of heat extraction of an evaporator of a heat pump unit under the conditions of dry bulb temperature, wet bulb temperature and enthalpy value of air when the heat supplementing equipment is started to operate; if the requirement is not met, increasing the model of the surface cooler until the requirement is met; if the requirement is met, selecting the surface cooler, and entering the next step;

C. calculating the annual target lifting temperature of the soil under the active heat supplementing working condition; the calculation period is 10 years and is used for allocating the initial investment generated by additionally arranging the surface cooler, and the calculation mode is as follows:

during calculation, the lifting value delta t of the soil temperature is taken as an independent variable, and the total cost C of heat supply and heating is obtained_ztAs a dependent variable, the soil lifting temperature when the sum of the heat supplement cost and the heating cost is minimum is taken as a target lifting temperature;

C_zt＝C_bt/n+C_qt+1.1×C_bx+1.1×C_zx(1)

C_bx＝p×ρ_sc_sV×(t_s0+Δt)/COP_b+p×(P_sw+P_sn+P_b) (2)

C_bx＝p×Q×(COP_i-1)/COP_i+p×(P_sw+P_sn) (3)

in the formula (1), C_ztThe total annual heat supply and heating cost is Yuan; c_btThe method is the initial investment of the surface cooler; c_qtAs a further part of the systemInvestment of (1), Yuan; c_bxAnnual operation cost of a system in a heat supply period is guaranteed; c_zxAnnual operating cost, yuan/year, for the heating period of the system; and n is the operation life of the system, and 10 years are taken.

In the formulae (2) and (3), ρ_sc_sIs the specific heat capacity of soil, J/(m)³DEG C.) and V is the volume (the hole number is × intervals) of the arrangement of the buried pipe heat exchange system²× buried depth), m³；t_s0At the present soil temperature, DEG C; delta t is the soil lifting temperature, DEG C; p is the local electricity price, yuan/kWh; COP_bEfficiency of heat pump set in heat supplementing condition (its magnitude depends on t)_s0，t_s0The smaller, the COP_bLarger), dimensionless; COP_iEfficiency of heat pump unit in heating condition (its magnitude depends on t)_s0+Δt，t_s0The smaller the + Δ t, the COP_iLarger), dimensionless; p_swThe power consumption of the outdoor water pump is kWh; p_snThe power consumption of the indoor water pump is kWh; p_bThe power consumption of the surface cooler is kWh.

D. Repeating the step C to complete the design calculation of other years needing active heat supplement according to the t of the year_s0+ Δ t as t for the next year_s0) (ii) a When the target soil temperature rise value is close to the soil temperature drop value caused by winter heating, the active heat supplement is not started, the operation mode is switched, and all the operation in the later period is passive heat supplement;

E. and outputting a result: the results include specific parameters of the surface air cooler, dry bulb temperature, wet bulb temperature and enthalpy of the air when the heat recovery device is started, target annual rise temperatures, and the sum of the heat recovery and heating costs.

F. And inputting the dry bulb temperature, the wet bulb temperature, the enthalpy value and the annual target rise temperature of the air when the heat supplementing equipment is started into a controller to control the operation of the system.

In conclusion, compared with solar energy heat compensation and air source heat pump heat compensation, the invention greatly reduces initial investment, when in active heat compensation, the efficiency of the heat compensation working condition is much higher than that of the heating working condition, an evaporator of the heat pump unit absorbs heat from outdoor air through a surface air cooler, and then the heat in the air is stored in underground soil through a buried pipe heat exchanger, thereby achieving the purpose of improving the soil temperature. During passive concurrent heating, do not open heat pump set, utilize the surface cooler directly to absorb the heat from outdoor air, then through the buried pipe heat exchanger with the heat in the air in the storage underground soil, play the effect of recovering soil temperature. The invention is particularly suitable for large-scale residential buildings which adopt the soil source heat pump for single heating and have obvious reduction of soil temperature after running for years, and ensures the long-term stable heating of the buried pipe ground source heat pump.

In the description above, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and thus the present invention is not limited to the specific embodiments disclosed above.