JPH0427453B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a direct contact heating and cooling system that uses a heat storage tank to directly transfer heat from a refrigerant to brine during heating.

[Prior art]

Traditionally, most buildings have been cooled by installing chiller equipment to match the maximum cooling load, but in recent years, the power demand for the buildings themselves has increased and the demand for electricity from various office automation devices has increased. As heat increases, the cooling load tends to increase, and the difference in power consumption between day and night tends to widen.

For this reason, air conditioners that store cold heat at night have been frequently proposed in recent years in order to suppress the power demand for daytime cooling of buildings and to equalize the power load.

In such a cold storage heat system, an ice storage type cooling device that uses ice as its cold heat source can store heat at a higher density than the conventional water storage type.
As the heat storage tank becomes more compact and the surface area of the heat storage tank decreases as the tank capacity decreases, heat loss decreases and heat storage becomes possible at even lower temperature levels, which reduces pump power and fan power. It has many advantages such as reduced power consumption, and is
It is also known for an invention related to a thermal storage type cooling device disclosed in Publication No. 38135.

As described above, a cooling device using ice heat storage includes a heat storage tank 1 incorporating a load heat exchanger 8 and a condenser 24 as shown in FIG. 3, and a compressor 3 for compressing refrigerant gas. , an air-cooled heat exchanger 23 that condenses or evaporates refrigerant gas, a refrigerant storage tank 5 that stores liquefied refrigerant, and a liquid cooled or heated by the load heat exchanger 8 to cool or heat air. A conventional example constructed from a fan coil unit 22 has been developed.

During cooling in the conventional device described above, the refrigerant is pressurized by the compressor 3 to a saturated vapor pressure corresponding to the condensation temperature or higher, as shown by the solid arrow, and then sent to the air-cooled heat exchanger 23 where it is liquefied. After passing through the refrigerant storage tank 5, the liquid is depressurized at the first expansion valve 18 to a saturated vapor pressure corresponding to a temperature 1 to 2 degrees C lower than the freezing point of the brine, and then flows from the lower part of the heat storage tank 1 through the nozzle 7 into the brine. is sprayed on.

The refrigerant liquid sprayed into the brine absorbs heat from the brine and evaporates, and then passes through the suction drum 2 and reaches the compressor 3.

Therefore, the brine in the heat storage tank 1 loses heat to the vapor of the refrigerant liquid and its temperature drops, producing ice crystals in the brine, and the ice crystals are stored in the heat storage tank 1 as a slurry with the brine.

The above operation is carried out until the required amount of ice is produced using electricity at night, and during the day, the load heat exchanger 8 is built into the heat storage tank 1, and the cold/hot water pump 21 is connected to the load heat exchanger 8. Cold water for cooling is sent, and
Heat exchange is performed with the brine in the heat storage tank 1, and the temperature of the cooling water is lowered.

The cooled water for cooling, whose temperature has dropped, exchanges heat with the cooling air in the fan coil unit 22, and then is sent again to the heat exchanger 8 by the cold/hot water pump 21, but the flow during cooling is This is indicated by a solid arrow in FIG.

In addition, during heating, as shown by the broken line arrow in FIG. 3, the refrigerant is pressurized by the compressor 3 to a saturated vapor pressure corresponding to the condensation temperature or higher, and then sent to the condenser 24 where it is liquefied. After passing through the refrigerant storage tank 5, the condensed liquid is depressurized to a predetermined saturated vapor pressure in the second expansion valve 19, and then evaporated in the air-cooled heat exchanger 23, and after being gasified, it passes through the suction drum 2 and is transferred to the compressor. 3.

On the other hand, the brine in the heat storage tank 1 used to cool the refrigerant gas takes away the heat from the refrigerant gas in the condenser 24 and rises in temperature, so the heat from the condensation of the refrigerant is stored in the heat storage tank 1. .

The above operation is performed using nighttime electricity until the necessary amount of heat is accumulated in the heat storage tank 1, and during the day, the hot water in the heat storage tank 1 is supplied to the fan coil unit 22 by the cold/hot water pump 21, and the fan coil unit After exchanging heat with the heating air at step 22, it is returned to the heat storage tank 1.

In addition, during heating, the pump 2 in the circulation path of the heat storage tank 1
5 is to be driven.

Moreover, in order to switch from the cooling time to the heating start time, all the switching valves 31 to 38 are respectively switched as appropriate.

As mentioned above, since the condenser 24 in the heat storage tank 1 is used during heating, the system is quite complicated, and the equipment cost is relatively high.
There was a problem with poor thermal efficiency.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned conventional problems, and can improve temperature efficiency by using a direct contact heat transfer method that directly transmits heat to brine using a heat storage tank for both air conditioning and heating. The purpose of this invention is to provide a direct contact heating and cooling device that can simplify the attached piping and valves.

[Structure of the invention]

To achieve the above object, the direct contact heating and cooling device of the present invention has a heat storage tank in which brine is stored so as to be in direct contact with a refrigerant during heating and cooling, and has a liquefied refrigerant reservoir at the bottom, and a heat storage tank that compresses refrigerant gas. A compressor, an air-cooled heat exchanger that condenses or evaporates refrigerant gas, a refrigerant storage tank that stores liquefied refrigerant, a heat exchanger that cools or heats the liquid using brine in the heat storage tank, and the liquid used for air conditioning. The heating/cooling means cools or heats the air.

The air conditioning system with the above configuration functions in the same way as the conventional system during cooling, but also during heating, the heat of the refrigerant is transferred directly to the brine using a heat storage tank to improve thermal efficiency. This system has been improved and simplified.

As the heating and cooling means, a unit such as a fan coil unit or an air handling unit can be adopted.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are schematic system diagrams of a direct contact heating and cooling device in an embodiment of the present invention.
The figure shows the state during cooling, and FIG. 2 shows the state during heating.

First, in FIGS. 1 and 2, brine is stored inside a heat storage tank 1 as a crystal can, and a liquefied refrigerant reservoir 40 is provided at the bottom of the tank. A nozzle 7 for blowing refrigerant is provided.

Next, a compressor 3 that compresses refrigerant gas, an air-cooled heat exchanger 23 that can condense or evaporate refrigerant gas,
A refrigerant storage tank 5 for storing liquefied refrigerant is provided.

Further, a heat exchanger 41 that cools or heats a liquid such as water using the brine in the heat storage tank 1, and a fan coil unit 22 that cools or heats air conditioning air using the liquid are provided, and these devices are connected. Switching valve 1 that can be opened and closed for each piping
1, 12, 13, 14, 15, 16, 17, 1st
An expansion valve 18 and a second expansion valve 19 are appropriately arranged.

Therefore, when the air conditioning system is cooling, the switching valves 11, 14, 15, 17 and the second expansion valve 19 shown in FIG. 1 are closed, and the switching valves 12, 13,
16 and the first expansion valve 18, the refrigerant is pressurized by the compressor 3 to a saturated vapor pressure corresponding to the condensation temperature or higher, and then sent to the air-cooled heat exchanger 23 and liquefied.

After passing through the refrigerant storage tank 5, this condensed liquid is depressurized at the first expansion valve 18 to a saturated vapor pressure corresponding to a temperature 1 to 2 degrees Celsius lower than the freezing point of the brine.
It is sprayed from the nozzle 7 into the brine from the lower part of the heat storage tank 1 and comes into direct contact with the brine.

The refrigerant liquid sprayed into the brine absorbs heat from the brine and evaporates, then passes through the switching valve 13 and reaches the compressor 3.

The temperature of the brine in the heat storage tank 1 decreases as heat is taken away by the vapor of the refrigerant liquid, and ice crystals are formed in the brine.

The ice crystals are stored in the storage tank 1 as a slurry with brine.

The brine preferably has a freezing point of -2 to -3°C, such as a 3 to 3.5% saline solution or a 5 to 10% ethylene glycol solution.

In this case, even if inexpensive seawater is used, the problem of corrosion is not serious because the temperature is below room temperature.

The above operation is performed until the required amount of ice is produced using electricity at night, and during the day, the brine in the heat storage tank 1 is supplied to the heat exchanger 41 by the brine pump 28, and heat exchanges with the cooling water for air conditioning. The cooling water whose temperature has decreased exchanges heat with the cooling air in the fan coil unit 22.

Next, during heating, each switching valve 12, 1 shown in FIG.
3, 16 and the first expansion valve 18 are closed, and each switching valve 1
1, 14, 15, 17 and the second expansion valve 19, the refrigerant gas whose pressure and temperature have been increased by the compressor 3 is blown directly into the brine in the heat storage tank 1 from the nozzle 7, and the refrigerant is inside the brine. The condensed and liquefied refrigerant is separated by gravity due to the difference in specific gravity with the brine, extracted from the liquefied refrigerant reservoir 40 at the bottom of the heat storage tank 1, and evaporated by the second expansion valve 19 and the air-cooled heat exchanger 23. and return to compressor 3.

On the other hand, the brine in the heat storage tank 1 increases the temperature by absorbing the heat of the refrigerant when the refrigerant gas is condensed, so that heat is stored therein.

In this case, the brine used during the cooling can be used as is.

The above operation is carried out at night using electricity late at night until the required amount of heat is accumulated in the heat storage tank, and during the day the brine in the heat storage tank 1 is pumped to the heat exchanger 4 by the brine pump 28.
1, and heat-exchanged hot water for heating is sent to the fan coil unit 22 to exchange heat with air for heating.

As described above, in the air conditioning system of the present invention, the heat of the refrigerant is transferred directly to the brine using the heat storage tank 1 not only during cooling but also during heating, so that the heating and cooling system of the present invention is superior to conventional cooling systems. The number of condensers and associated piping and valves can be reduced by about half, making it possible to configure a very simple system.

〔Effect of the invention〕

As explained above, the direct contact heating and cooling system of the present invention is a direct contact type in which the heat of the refrigerant is directly transferred to the brine using a heat storage tank even during heating, so the equipment for heat exchange and the This has the effect of reducing the number of attached piping and valves by approximately half, making the system configuration extremely simple.

Furthermore, the use of the direct contact method reduces the minimum temperature difference that is conventionally required when heat exchange is required, which has the advantage of improving temperature efficiency accordingly.

Furthermore, if the piping is simplified, the heat radiation loss will be reduced accordingly, and the performance of the air conditioning system will be improved.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic system diagrams of a direct contact heating and cooling device according to an embodiment of the present invention, with FIG. 1 showing the cooling state, and FIG. 2 showing the heating state. FIG. 3 is a schematic diagram of a conventional heating and cooling system. 1... Heat storage tank, 3... Compressor, 5... Refrigerant storage tank, 22
... fan coil unit, 23 ... air-cooled heat exchanger, 40 ... liquefied refrigerant reservoir, 41 ... heat exchanger.

Claims (1)

[Claims] 1. A heat storage tank in which brine is stored so as to be in direct contact with refrigerant during heating and cooling, and has a liquefied refrigerant reservoir at the bottom, and a compressor that compresses refrigerant gas;
An air-cooled heat exchanger that condenses or evaporates refrigerant gas, a refrigerant storage tank that stores liquefied refrigerant, and a heat exchanger that cools or heats a liquid with brine in the heat storage tank, and the liquid cools or heats air. A direct contact heating and cooling device consisting of heating and cooling means.