CN100451492C - Integrated air-conditioning system of solar-assisted soil source CO2 trans-critical heat pump - Google Patents

Abstract

The invention discloses a solar-energy soil ultra-critical carbon dioxide heat pump air-conditioning system. The invention comprises an ultra-critical carbon dioxide heat pump medium circulator, a solar-energy collector, an underground tube heat exchanger, and an indoor air-conditioning tube. The invention arranges heat exchange coil tube, evaporator/gas cooler in the heat accumulating box, via four-way valve and valves to connect them into one air-conditioning system. The invention can work in five modes as heating, refrigerating, heating water, heating-heating water, and refrigerating-heating water, to heat water, refrigerate and supply heat.

Description

Solar-assisted soil source transcritical carbon dioxide heat pump integrated air conditioning system

technical field

The invention belongs to the technical scope of solar energy utilization and air conditioning, and in particular relates to a comprehensive air conditioning system of solar energy assisted soil source transcritical carbon dioxide heat pump. Specifically, the solar heat collection system is combined with the soil source transcritical carbon dioxide heat pump air-conditioning system, and through the coordination and cooperation of the solar heat collection system, the buried pipe heat exchange system and the heat pump air-conditioning system, a triple supply of heating, cooling and hot water is formed. comprehensive system.

Background technique

As a natural substance, carbon dioxide is an ideal refrigerant. Its advantages are non-toxic, non-flammable, zero ODP value, low greenhouse effect, low price, no need for recycling, and no unforeseen side effects on the environment. Currently, as a hot research field in the refrigeration industry, the research work on transcritical carbon dioxide refrigeration and air-conditioning systems is rapidly developing around the world, and many researchers predict that carbon dioxide will be the next-generation refrigerant. In the transcritical carbon dioxide cycle, the exothermic process of carbon dioxide is carried out under supercritical pressure, so there is a large temperature drop. This process is especially suitable for heating domestic hot water. Carbon dioxide heat pump water heaters are currently recognized to be superior to R22, R134a and other conventional working fluid heat pump water heaters. Studies by scholars from Austria, Norway, Japan and other countries have shown that the annual average COP value of this heat pump hot water system can reach more than 3, and it can still provide hot water at 90 °C in an environment of -20 °C. Compared with electric heating or gas water heaters, the energy consumption 75% lower.

With the continuous improvement of people's comfort requirements, the energy consumption for air conditioning and domestic hot water continues to increase. However, in the prior art, the air-conditioning system and the domestic hot water system for small households are generally separated, and each has its own independent loop system. Moreover, the operation cycle of the air-conditioning equipment is very intermittent, which causes the equipment to be idle and increases the cost. For an independent solar heat collection system, it is seriously affected by weather factors, and there is a great deal of intermittency and instability; for an independent soil source heat pump system, especially in northern regions, the heating time is much longer than the cooling time, which will cause soil temperature fluctuations. As a result, the coefficient of performance will continue to decrease.

Contents of the invention

The purpose of the present invention is to provide a solar energy assisted soil source transcritical carbon dioxide heat pump integrated air conditioning system.

In the technical solution adopted by the present invention, the solar-assisted soil-sourced transcritical carbon dioxide heat pump comprehensive air-conditioning system includes four parts: a solar heat collection system, an underground pipe heat exchange system, a transcritical carbon dioxide heat pump air-conditioning system and an indoor fan coil system. The so-called transcritical carbon dioxide cycle means that carbon dioxide absorbs heat in the evaporator below the critical pressure and releases heat in the cooler (instead of the "condenser" in the conventional compression refrigeration system) under the supercritical pressure condition .

The solar heat collection system is connected to the heat storage tank 11 through the heat collector water inlet valve 13 and the heat collector water outlet valve 12 and the first water pump 10 on both sides of the solar heat collector 9;

The soil source uses an underground pipe heat exchange system to provide a low-level heat source, and the underground pipe heat exchanger 14 passes through the first valve 16, the second water pump 15, the second valve 17, and the first evaporator/gas cooler 3. The left road, the third valve 18 and the fourth valve 19 are connected into a loop, and the ninth valve 25 is connected in parallel at both ends of the series loop of the first valve 16, the underground pipe heat exchanger 14, and the fourth valve 19; the second valve 17 The two ends are respectively connected to the water tank heat exchange coil 20 in the hot water storage tank 11 through the fifth valve 21, the sixth valve 22, the eighth valve 24, and the seventh valve 23, and one end of the water tank heat exchange coil 20 passes through the sixth valve 22. The tenth valve 26 is connected to the nodes of the eleventh valve 27 and the fifteenth valve 33, and the other end of the water tank heat exchange coil 20 is connected to the second evaporator/gas cooling through the seventh valve 23 and the fourteenth valve 32 The right side of the device 7 is connected to the node of the twelfth valve 30, and the fifteenth valve 33 is respectively connected to the right side of the second evaporator/gas cooler 7 through the third water pump 29 and the thirteenth valve 31 connected to each other. and the indoor fan coil system 28; the indoor fan coil system 28 is connected to the twelfth valve 30;

The compressor 1, the first four-way valve 2, the liquid storage tank 8, and the internal heat exchanger 5 of the transcritical carbon dioxide heat pump air-conditioning system are connected in series to form a circuit, and are cooled by the first four-way valve 2, the first evaporator/gas The right path of the device 3, the second four-way valve 4, the left path of the second evaporator/gas cooler 7, and the first four-way valve 2 are connected into a loop; the internal heat exchanger 5 is also connected with the second four-way valve 4 , Throttle valve 6 forms a loop.

The heat pump air-conditioning system uses critical carbon dioxide as a working medium, and the main components and piping system of the heat pump air-conditioning system should meet the pressure resistance requirement of 15MPa.

The water circuit system and refrigeration system of the solar heat collector can be independent of each other.

The heat storage tank 11 has a built-in water tank heat exchange coil 20, which can be used not only as a heat storage tank for providing domestic hot water, but also as a low-level heat source for providing heat.

The low-level heat source that provides heat (if the pure soil source is used as the low-level heat source, the temperature is about 5-20° C.) adopts a separate heat storage tank circuit or a series circuit between the soil source and the heat storage tank.

The beneficial effect of the present invention is that the solar heat collection system, the underground pipe heat exchange system, and the transcritical carbon dioxide heat pump air-conditioning system are closely coordinated to adapt to heating, cooling, heating + hot water, cooling + hot water in different seasons in spring, summer, autumn and winter , hot water and other different needs, to meet the requirements of compact equipment, comprehensive functions, and energy saving.

The present invention firstly uses carbon dioxide as a green working medium, and secondly adopts a solar energy heat collection system, utilizes renewable solar energy, and has the advantages of energy saving and environmental protection. The soil is used again as a low-level heat source, which improves the coefficient of performance and avoids the "urban heat island effect" caused by the use of air heat exchange equipment.

Description of drawings

Fig. 1 is a schematic diagram of the structure of a solar-assisted soil-sourced transcritical carbon dioxide heat pump integrated air-conditioning system.

In the figure: 1-compressor; 2-first four-way valve, 4-second four-way valve; 3-first evaporator/gas cooler; 7-second evaporator/gas cooler; 5-internal replacement Heater; 6-throttle valve; 12-collector outlet valve; 13-collector inlet valve; 8-liquid storage tank; 9-heat collector; 10-first water pump, 15-second water pump, 29-the third water pump; 11-hot water storage tank; 14-underground pipe heat exchanger; 20-water tank heat exchange coil; 28-fan coil system; the rest are two-way valves.

Detailed ways

Under different climate conditions, this system can achieve three functions of heating water, heating and cooling through the coordination and cooperation of solar heat collection system, underground pipe system and heat pump air conditioning system. In general, this system has 5 working modes, which are: (1) hot water working condition; (2) heating working condition; (3) heating + hot water working condition; (4) cooling working condition; (5) Refrigeration + hot water working conditions. The following are introduced respectively:

(1) Hot water condition

a) In the case of sufficient light intensity, without turning on the heat pump system, the solar energy composed of the solar collector 9, the collector water inlet valve 13, the hot water storage tank 11, the first water pump 10 and the collector outlet valve 12 is The hot water collection circuit system can directly reach the predetermined temperature as the bathing temperature, and the range is about 30-60°C.

b) When the light intensity is insufficient, the compressor 1 is turned on, and the first four-way valve 2 and the second four-way valve 4 are respectively switched to enter the heat pump heating mode. The low-level heat source adopts the soil source, which is between 5-20°C; the soil source consists of the underground pipe heat exchanger 14, the first valve 16, the second water pump 15, the second valve 17, and the first evaporator/gas cooler 3 , The third valve 18 and the fourth valve 19 are composed. The loop of the water tank heating system consists of the second evaporator/gas cooler 7, the third water pump 29, the fifteenth valve 33, the tenth valve 26, the sixth valve 22, the water tank heat exchange coil 20, the seventh valve 23 and the tenth Four valves 32 are formed.

(2) Heating condition

First, activate the heat pump heating mode. The hot end circuit is composed of a fan coil system 28 , a twelfth valve 30 , a second evaporator/gas cooler 7 , a third water pump 29 and a thirteenth valve 31 . The low-level heat source circuit is divided into the following two situations:

a) When the temperature of the water tank is similar to that of the soil source, the heat source of the solar heat storage tank and the soil heat source can be used alternately. The soil source consists of an underground pipe heat exchanger 14, a first valve 16, a second water pump 15, a second valve 17, a first evaporator/gas cooler 3, a third valve 18 and a fourth valve 19, and the water storage The tank circuit is composed of the water tank heat exchange coil 20, the seventh valve 23, the eighth valve 24, the first evaporator/gas cooler 3, the third valve 18, the ninth valve 25, the second water pump 15, the fifth valve 21 and The sixth valve 22 is formed.

b) When the temperature of the water tank is higher than the temperature of the soil source, two low-level heat sources, the soil heat source and the solar heat storage tank, can be used at the same time to further increase the temperature of the low-level heat source. The mixed low-temperature heat source loop consists of a buried heat exchanger 14, a valve first gate 16, a second water pump 15, a fifth valve 21, a sixth valve 22, a water tank heat exchange coil 20, a seventh valve 23, an eighth valve 24, The first evaporator/gas cooler 3, the third valve 18 and the fourth valve 19 are composed.

(3) Cooling condition

a) When the refrigeration load is small, the compressor may not be started, and only the cooling capacity of the soil source is used to perform water circulation in the underground pipe heat exchanger and the fan coil system. The circulation loop consists of the underground pipe heat exchanger 14, the first Valve 16, second water pump 15, second valve 17, eighth valve 24, fourteenth valve 32, twelfth valve 30, fan coil system 28, thirteenth valve 31, fifteenth valve 33, tenth A valve 27 and a fourth valve 19 are formed.

b) When the cooling load is large, the compressor 1 is started, and the first four-way valve 2 and the second four-way valve 4 are respectively switched to enter the cooling mode. At this time, the low-level heat source is the fan coil system, and the circuit is composed of the fan coil system 28 , the twelfth valve 30 , the second evaporator/gas cooler 7 , the third water pump 29 and the thirteenth valve 31 . The hot end absorbs heat through the soil source, and the cooling circuit consists of an underground pipe heat exchanger 14, a first valve 16, a second water pump 15, a second valve 17, a first evaporator/gas cooler 3, a third valve 18 and The fourth valve 19 is formed.

(4) Heating + hot water working condition

a) When the solar heat collection system can provide enough domestic hot water, the low-level heat source in the above-mentioned second heating condition can be used with a separate heat storage tank circuit or a series circuit between the soil source and the heat storage tank.

b) When the solar heat collection system cannot provide enough domestic hot water, temporarily switch the heating circuit consisting of the fan coil system 28, the twelfth valve 30, the second evaporator/gas cooler 7, the pump 29 and the valve 31 Composed of the second evaporator/gas cooler 7, the third water pump 29, the fifteenth valve 33, the tenth valve 26, the sixth valve 22, the water tank heat exchange coil 20, the seventh valve 23 and the fourteenth valve 32 tank heating circuit. When the temperature of the water tank reaches the specified temperature, switch back again.

(5) cooling + hot water working conditions

a) When the solar heat collection system can provide enough domestic hot water, the water circuit system and the refrigeration system through the solar heat collector can be independent of each other. The refrigeration system operates with reference to the third refrigeration working condition above.

b) When the solar heat collection system cannot provide enough domestic hot water, temporarily install the underground pipe heat exchanger 14, the first valve 16, the second water pump 15, the second valve 17, the first evaporator/gas cooler 3, The cooling circuit composed of the third valve 18 and the fourth valve 19 is switched to the water tank heat exchange coil 20, the seventh valve 23, the eighth valve 24, the first evaporator/gas cooler 3, the third valve 18, and the ninth valve 25. The second water pump 15, the fifth valve 21 and the sixth valve 22 form a water tank heating circuit.

Claims (5)

1. solar-assisted soil source CO 2 trans-critical heat pump integrated air-conditioning system, described solar-assisted soil source CO 2 trans-critical heat pump integrated air-conditioning system comprises solar thermal collection system, heat transfer system of underground heat exchanger, CO 2 trans-critical heat pump air-conditioning system and indoor fan coil system four parts, it is characterized in that

Described solar thermal collection system is for to be connected to hot water storage tank (11) by heat collector inlet valve (13) and heat collector flowing water Valve (12), first water pump (10) respectively on the both sides of solar thermal collector (9);

Described soil source adopts heat transfer system of underground heat exchanger that low level heat energy is provided, the left side one tunnel, the 3rd valve (18) and the 4th valve (19) of first valve (16), second water pump (15), second valve (17), first evaporator (3) of leading up to of underground heat exchanger (14) connects into the loop, and the 9th valve (25) is connected in parallel on the two ends of the series loop of first valve (16), underground heat exchanger (14), the 4th valve (19); Second valve (17) two ends are respectively by the 5th valve (21), the 6th valve (22) and the 8th valve (24), water tank heat exchange coil (20) in the same hot water storage tank of the 7th valve (23) (11) connects, water tank heat exchange coil (20) one ends are by the 6th valve (22), the tenth valve (26) and the 11 valve (27), the node of the 15 valve (33) connects, water tank heat exchange coil (20) other end is by the 7th valve (23), the 14 valve (32) is connected with the right one road of second evaporator (7) and the node of the 12 valve (30), and the 15 valve (33) is by interconnective the 3rd water pump (29), the 13 valve (31) is connected respectively to the right one road and the indoor fan coil system (28) of second evaporator (7); Indoor fan coil system (28) is connected with the 12 valve (30) again;

The compressor of described CO 2 trans-critical heat pump air-conditioning system (1), first cross valve (2), fluid reservoir (8), internal exchanger (5) are connected into the loop, and the left side one tunnel and first cross valve (2) of the right one tunnel by first cross valve (2), first evaporator (3), second cross valve (4), second evaporator (7) connect into the loop; Wherein internal exchanger (5) is also formed the loop with second cross valve (4), choke valve (6).

2. according to the described solar-assisted soil source CO 2 trans-critical heat pump integrated air-conditioning system of claim 1, it is characterized in that described CO 2 trans-critical heat pump air-conditioning system adopts critical carbon dioxide as working medium.

3. according to the described solar-assisted soil source CO 2 trans-critical heat pump integrated air-conditioning system of claim 1, it is characterized in that the water loop system and the refrigeration system of described solar thermal collector can be separate.

4. according to the described solar-assisted soil source CO 2 trans-critical heat pump integrated air-conditioning system of claim 1, it is characterized in that, described hot water storage tank (11) inner water-tank heat exchange coil (20) both can be used as the hot water storage tank that the domestic hot-water is provided, and can be used as the low level heat energy that heat is provided again.

5. according to the described solar-assisted soil source CO 2 trans-critical heat pump integrated air-conditioning system of claim 4, it is characterized in that the described low level heat energy of heat that provides adopts independent hot water storage tank loop or soil source and hot water storage tank series loop.

Images