RU2679484C1 - Heat pump installation for heating and hot water supply - Google Patents

Abstract

FIELD: engines and pumps.SUBSTANCE: invention relates to the heating systems with heat pumps using the heat from low-temperature sources for independent heating and hot water supply. Heat pump installation contains a heat pump with an evaporator, a condenser, an expansion valve and a placed in a sealed casing compressor, as well as external horizontal circuit with a main ground tubular heat exchanger, as well as automatic controller for the heat pump installation operation control, and differs in that, in order to restore the soil thermal potential, the external horizontal circuit additionally contains an auxiliary tubular ground heat exchanger placed in the soil directly below the main ground heat exchanger, and in the compressor hermetic casing there is additionally a closed cavity connected to the auxiliary ground heat exchanger by pipelines so that a closed loop for the process liquid heat carrier circulation is formed, and the heat pump installation includes the additional hydraulic pump to provide the process liquid heat carrier circulation.EFFECT: objective of the proposed invention is enabling of the compression-type HPI with a horizontal ground external circuit operation efficiency by the of the soil thermal balance regular restoration in the external ground circuit heat exchanger area, as well as increase in the HPI compressor operation reliability by the compressor parts lubrication and cooling conditions improvement.8 cl, 3 dwg

Description

The invention relates to heat pump units (HPU) using low-temperature soil heat for autonomous heating and hot water supply of premises.

It is known that during the long-term operation of such HPUs, their efficiency decreases gradually due to soil overcooling around the soil heat exchanger of the primary circuit of the heat pump. A partial restoration of the thermal potential of the soil in the area where the soil heat exchanger is located due to the natural heat influx from the surrounding soil layers is possible only during the termination of operation of the HPP in the inter-heating period, which complicates the use of the HPU for a long stable supply of heat and hot water to the premises.

Known technical solutions aimed at improving the efficiency of TNU by restoring and maintaining the thermal potential of the soil.

A known system of autonomous heat supply to consumers based on installations using low-potential geothermal sources (patent RU No. 2350847). The system includes a ground-water compression heat pump, an internal circuit of a heat pump with a high temperature coolant, an external circuit of a heat pump with a heat exchanger with a low temperature coolant, as well as a solar collector, a tank for hot water supply, a system for controlling heat fluxes of the system, liquid pumps for pumping coolants and hot water supply.

An increase in the efficiency of the heat supply system here is achieved through the use of solar energy to heat the coolant in the low-potential coolant circulation circuit during the heating period, at low solar radiation intensity, and to restore the temperature regime of the wells during the heating season with the simultaneous generation of heat for hot water supply using solar collectors and using the potential of chilled wells to cool rooms, as well as ensuring system independence heating from a centralized power supply system.

The disadvantage of this invention is the need, in addition to a heat pump, to equip the solar collector circuit, which greatly complicates the design and increases the cost of such a heat supply system.

In addition, the beneficial use of excess heat generated during operation of the HPU compressor is not provided. This heat is uselessly dissipated into the environment, which leads to a decrease in the efficiency of the heat supply system.

Closest to the claimed technical solution is an autonomous heating system (RF patent for utility model No. 140455).

The system includes a low-potential coolant circulation circuit with a ground heat exchanger, the input of which is connected to the output of the heat pump evaporator and a heating system containing a heat pump condenser connected by a pipeline to heating devices, and is characterized in that it is additionally equipped with a second ground heat exchanger and a switching device including two hollow cylinders mounted vertically, with conical valves placed inside them, the tapered parts of which are connected to the rods pistons, piston bottoms are placed in sealed vessels with gas located in the lower parts of the hollow cylinders connected to the exits of the soil heat exchangers, and above the hollow cylinders there is a rocker whose axis is located in the middle between the hollow cylinders, while the expanding parts of the cone-shaped valves are connected via articulated couplings shoulders of the rocker arm, on which a sealed tube is fixed with a ball placed in it, the upper parts of the hollow cylinders being connected by a pipe to the inlet of the evaporator pump, and soil heat exchangers are located at a distance of 5 ... 25 m from each other.

Due to the alternate shutdown of the first and second soil heat exchanger from participation in the autonomous heating of the room, the soil in the area of the disconnected heat exchanger naturally heats up. The technical result is the elimination of excessive hypothermia at the location of the soil heat exchanger.

In this utility model, it is proposed to use two horizontal soil external contours instead of one, as is usually accepted in the designs of HPU with a horizontal soil external contour. However, in this case, it will be necessary to occupy a twice as large plot of land near the house for horizontal soil external contours, and the amount of excavation required for this will increase significantly. All this will lead to a significant increase in cost and lower availability for the population of a heating system with HPU.

In addition, the proposed utility model uses a rather complicated device to switch the operation of the heating system from one horizontal soil external circuit to another. This will lead to a decrease in reliability and complicate the operation of the heat pump installation. As a result, the attractiveness and accessibility of heating systems with HPU will decrease, especially for individual consumers in private homes.

In addition, in this utility model, it is assumed that the restoration of the heat balance of the soil in the heat exchanger zone of the temporarily disconnected horizontal soil external contour will occur only due to the natural heat influx from the surrounding soil layers. However, it is known that the natural process of restoring the heat balance of the soil, without an organized supply of thermal energy from the outside, is very lengthy, and the soil in the zone of the switched-off heat exchanger, especially in winter, may not have time to warm up by the time it is necessary to connect this soil external circuit. As a result, the efficiency of TNU, even in the presence of two horizontal soil external circuits, will gradually decrease.

In addition, the excess heat that is removed from the compressor of the HPU by the lubricant circulating in the compressor casing is mainly dissipated through the casing walls into the environment. Such useless heat loss leads to a decrease in the efficiency of the HPU.

The objective of the proposed invention is to ensure the efficiency of the compression type HPU with a horizontal soil external circuit by regularly restoring the heat balance of the soil in the heat exchanger zone of the external soil circuit, as well as improving the reliability of the TNU compressor by improving the lubrication and cooling conditions of the compressor parts.

This problem is solved due to the fact that the heat pump installation contains a heat pump with an evaporator, a condenser, an expansion valve and a compressor placed in a sealed enclosure, as well as an external horizontal circuit with a main soil tube heat exchanger, as well as an automatic controller for controlling the operation of the heat pump installation, and differs the fact that, in order to restore the thermal potential of the soil, the external horizontal circuit additionally contains an auxiliary tubular ground heat exchange a nickel placed in the soil directly under the main soil heat exchanger, and in the hermetic casing of the compressor there is additionally a closed cavity connected by pipelines to the auxiliary soil heat exchanger so that a closed loop is formed for the circulation of the process liquid coolant, and the heat pump installation has an additional hydraulic pump to ensure circulation of technological liquid coolant.

Antifreeze can be used as a process liquid coolant.

The dimensions of the main and auxiliary heat exchangers of the external horizontal circuit in the transverse and longitudinal directions can be equal to each other, and between the main and auxiliary heat exchangers of the external circuit there can be a soil layer with a thickness of 50 ... 100 mm.

The closed cavity in the hermetic casing of the compressor may be an annular hermetic cavity formed by double walls of the casing and located around the perimeter of the casing.

An oil temperature sensor can be located in the compressor crankcase, the signals from which are transmitted to the automatic controller. In a closed cavity in an airtight casing of the compressor, a sensor for monitoring the temperature of the process liquid coolant can be located, and the signals from the sensor are transmitted to the automatic controller. A hydraulic pump circulating the process fluid may have an adjustable capacity, which can be changed by commands of an automatic controller.

The content of the claimed invention is illustrated by the following figures: FIG. 1 is a schematic diagram of HPU for heating and hot water supply; FIG. 2 - compressor cooling circuit; FIG. 3 - layout of the placement of heat exchanger external horizontal circuit.

ТНУ includes (Fig. 1) evaporator 1, compressor 2, condenser 3, expansion valve 4, external horizontal circuit 5 with the main soil tube heat exchanger 6 and auxiliary tube soil heat exchanger 7, an automatic controller for controlling the operation of the HPU (not shown in Fig.) , a hydraulic pump 8 for circulating the non-freezing liquid heat carrier through the main soil tubular heat exchanger, an additional hydraulic pump 9 for circulating the process liquid heat carrier i. An oil temperature sensor 12 is located in the compressor crankcase (Fig. 2), the signals from which are transmitted to the automatic controller.

The compressor 2 (Fig. 2) has a sealed casing 10 in which a closed sealed cavity 11 is made. The closed cavity in the sealed compressor casing may be an annular sealed cavity formed by double walls of the casing and covering the entire perimeter of the casing. A closed cavity in a sealed compressor casing may also be a local sealed cavity formed by double walls of the casing and covering part of the perimeter of the casing. In a closed cavity in an airtight casing of the compressor is a sensor 13 for monitoring the temperature of the process liquid coolant, and the signals from the sensor are transmitted to the automatic controller.

The main 6 and auxiliary 7 heat exchangers of the external horizontal soil circuit (Fig. 3) are made in the form of systems of horizontally located interconnected pipelines.

The auxiliary heat exchanger 7 is located in the soil at a depth exceeding the depth of freezing of the soil in this region, and then is sprinkled with a layer of soil with a thickness of 50 ... 100 mm. On top of this soil layer directly above the auxiliary heat exchanger, the main heat exchanger 6 is laid so that it is also at a depth exceeding the depth of freezing of the soil. After laying, the main heat exchanger is sprinkled with soil to ground level. Moreover, the additional amount of earthwork that must be performed to place the main heat exchanger directly above the auxiliary heat exchanger is very insignificant.

The dimensions A and B (Fig. 3) of the main and auxiliary heat exchangers of the external circuit in the transverse and longitudinal directions are equal to each other, which is important for organizing the process of heating the soil in the area of the main heat exchanger. At the same time, the area of land required to accommodate these two heat exchangers (instead of only one - the main one) practically does not increase.

The main heat exchanger of the external horizontal soil circuit 6 (Fig. 1) is connected by pipelines to the heat pump evaporator 1 and non-freezing liquid coolant is circulated along the formed closed loop.

The auxiliary heat exchanger 7 (Figs. 1 and 2) is connected by pipelines with a closed sealed cavity 11 in the casing 10 of the compressor, as a result of which a closed loop is formed, along which there is a circulation of non-freezing technological liquid coolant, for example, antifreeze. The pumping of the liquid process fluid in a closed circuit is provided by a hydraulic pump 9, which has an adjustable capacity.

TNU works as follows. The main horizontal tubular heat exchanger 6 selects low-temperature heat energy from the soil and transfers it to the refrigerant in the heat pump evaporator 1. Then the refrigerant vapor is compressed and heated in the compressor 2. In the condenser 3, heat exchange occurs between the heated refrigerant vapor and water intended for heating and hot water supply.

During operation of compressor 2, a lubrication and cooling system provides lubrication of compressor parts and removal of excess heat from them. At the same time, part of the heat taken from the compressor by the circulating liquid lubricant transfers, due to thermal conductivity, through the inner wall of the sealed cavity 11 in the compressor casing to the technological liquid coolant circulating in a closed circuit. The heated process liquid coolant enters the auxiliary heat exchanger 7 of the external horizontal soil circuit, where heat is exchanged between the process liquid coolant and the surrounding soil.

In the process of long-term operation of the HPU, the soil is gradually cooled around the main soil heat exchanger 6 of the external circuit. However, due to the fact that part of the heat from the heated process fluid through the pipe walls of the auxiliary heat exchanger 7 is transferred to the surrounding soil, there is an increase in the temperature of the soil around the auxiliary heat exchanger 7, as well as a gradual restoration of the thermal potential of the soil in the area of the main heat exchanger 6 of the external circuit located in close proximity to the auxiliary heat exchanger.

Due to the fact that the sizes A and B (Fig. 3) of the main and auxiliary heat exchangers of the external circuit in the transverse and longitudinal directions are equal to each other, soil heating occurs in the entire area near the main heat exchanger of the external circuit.

Thus, heating of the soil and restoration of its energy potential occurs year-round, both due to natural heating from solar heat entering the soil in the warm season, and as a result of regular removal of excess heat from the compressor into the soil during operation of the heat pump. This allows you to significantly increase the efficiency and stability of the TNU.

During operation of the heat pump, an automatic controller (not shown in Fig.) Maintains the temperature of the oil in the compressor crankcase in a predetermined range to ensure the best conditions for lubrication and cooling of compressor parts, and also does not allow boiling of the process fluid to prevent deterioration of heat transfer processes in a closed circuit for circulation of technological liquid coolant. To do this, an oil temperature control sensor 12 is installed in the compressor crankcase (Fig. 2), the signals from which are transmitted to the automatic controller, and a sensor 13 for monitoring the temperature of the process liquid coolant is installed in a closed cavity in the sealed compressor casing, the signals from which are also transmitted to the automatic controller . The hydraulic pump 9 (Fig. 1), which ensures the circulation of the process fluid in a closed circuit, has an adjustable capacity. Depending on the temperature level of the oil in the compressor crankcase and the temperature level of the technological liquid coolant in a closed cavity in the hermetic casing of the compressor, the automatic controller sends commands to increase or decrease the speed of the hydraulic pump 9, which, in turn, increases or decreases the pumping speed of the technological liquid closed loop coolant. This allows you to adjust the amount of heat taken by the process liquid coolant from the liquid lubricant and maintain the oil temperature in the compressor crankcase in a given range. The change in the pumping speed of the heated process fluid through the auxiliary heat exchanger of the external circuit also avoids boiling of the process fluid due to a change in the amount of heat transferred from the process fluid to the surrounding soil through the walls of the heat exchanger tubes.

As a result of maintaining the optimum temperature of the oil in the compressor crankcase and reducing thermal loads on the compressor parts, due to the organization of their effective cooling, the reliability of the TNU compressor increases.

Thus, the implementation of the proposed invention allows to increase the efficiency of HPU due to the use of excess heat removed from the compressor to regularly restore the heat balance of the soil in the heat exchanger zone of the external soil circuit, as well as to increase the reliability of the HPU compressor due to improved lubrication and cooling of compressor parts.

Claims (8)

1. A heat pump installation comprising a heat pump with an evaporator, a condenser, an expansion valve and a compressor placed in a sealed enclosure, as well as an external horizontal circuit with a main soil tube heat exchanger, as well as an automatic controller for controlling the operation of the heat pump installation, characterized in that, for the purpose of to restore the thermal potential of the soil, the external horizontal circuit further comprises an auxiliary tubular soil heat exchanger located directly in the soil continuously below the main ground heat exchangers and the compressor hermetic casing further has a closed cavity, connected by pipelines with auxiliary ground heat exchangers so as to form a closed circuit for circulating the process liquid coolant, and consisting of the heat pump system has an additional hydraulic pump for circulating the process liquid coolant. 2. The heat pump installation according to claim 1, characterized in that the dimensions of the main and auxiliary heat exchangers of the external horizontal circuit in the transverse and longitudinal directions are equal to each other. 3. The heat pump installation according to claim 1, characterized in that between the main and auxiliary heat exchangers of the external circuit there is a soil layer with a thickness of 50 ... 100 mm. 4. The heat pump installation according to claim 1, characterized in that the closed cavity in the sealed casing of the compressor is an annular sealed cavity formed by double walls of the casing and located around the perimeter of the casing. 5. The heat pump installation according to claim 1, characterized in that the compressor crankcase has an oil temperature control sensor, the signals from which are transmitted to the automatic controller. 6. The heat pump installation according to claim 1, characterized in that in the closed cavity in the hermetic casing of the compressor there is a sensor for monitoring the temperature of the process liquid coolant, the signals from which are transmitted to the automatic controller. 7. The heat pump installation according to claim 1, characterized in that the hydraulic pump that circulates the process liquid coolant has an adjustable capacity, which varies according to the instructions of the automatic controller. 8. The heat pump installation according to claim 1, characterized in that antifreeze is used as the process liquid coolant.

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