JPH07305866A - Refrigerant natural circulation type cooling and heating system - Google Patents

Abstract

PURPOSE:To provide cooling and heating system, in which cooling and heating are effected by the natural circulation of refrigerant, by a method wherein a cold heat source is provided on the upper part of a building and a hot heat source is provided individually and respectively at the lower part of the building while the cold heat source at the upper part of the building is employed in cooling and the lower hot heat source is employed in heating. CONSTITUTION:A condenser heat exchanger in a cold heat source 1, in which refrigerant, whose phase is changed, is cooled and liquefied, is arranged at a part higher than a fan coil unit 2 and a closed circuit, connected through a refrigerant solution pipe 3 and a refrigerant gas pipe 4, is constituted and refrigerant is evaporated in a heat exchanger 22 in the fan coil unit 2 in respective rooms to cool the room upon cooling while a hot heat source 5 is provided at the lowermost part and the lower ends of refrigerant pipes 3, 4 are connected to the heat exchanger in the hot heat source 5 while the refrigerant is evaporated by heating a heat exchanger 51 upon heating and the refrigerant is condensed and liquefied in the fan coil unit 2 to radiate heat and effect room heating. A control device 6, closing valves 5a, 5b upon cooling and closing valves 1a, 1b upon heating to intercept the circuit, a refrigerant pressure or temperature sensor 7 and a liquid level sensor 8 are provided in this system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant natural circulation cooling and heating system in which two separate heat sources are installed above and below a building.

[0002]

2. Description of the Related Art Conventionally, as a system in which a refrigerant is naturally circulated in a fan coil unit by utilizing a pressure difference caused by a phase change of the refrigerant to cool the refrigerant, a refrigerant that changes the phase is cooled as shown in FIG. A fan coil unit b in which an absorption refrigerator a that is a liquefied cold heat source is installed in each room in the building.
Installed at a position higher than b, the cooling heat source and the fan coil unit are connected by a refrigerant liquid transfer pipe c and a refrigerant gas transfer pipe d to form a closed circuit in which the refrigerant circulates, and heat is exchanged at the cold heat source. A refrigerant circulation type cooling and heating system is known in which the refrigerant is supplied to a fan coil unit to cool each room, and when the heating is necessary, the absorption type refrigerator is switched to serve as a heat source to enable heating operation.

[0003]

2. Description of the Related Art In this refrigerant circulation type air conditioning system, since the heat source a is installed above the fan coil units b ... B installed in each room in the building,
Since the refrigerant naturally circulates during the cooling operation, it does not require a transfer power such as a pump, but during the heating operation, it transfers the pump e etc. to return the liquefied refrigerant that has passed through the heat exchanger of the fan coil unit to the heat source. In addition to the need for power, the running cost is high, and a refrigerant tank f for securing a liquid head of the refrigerant is provided directly above the pump e so that the pump does not cause a cavitation phenomenon due to a shortage of the refrigerant liquid.
It is uneconomical because the amount of refrigerant to be filled is large because it is necessary to secure a sufficient amount of refrigerant in the tank, and the risk of leakage increases, and the float that controls the operation of the pump is also required. A control device g such as a switch and a refrigerant liquid return pipe h are required, and not only running cost but also initial cost is high.

Further, during a low load cooling operation or the like, the supply amount of the refrigerant liquid to the heat exchanger of the fan coil unit increases and the refrigerant liquid that cannot be completely evaporated remains in the heat exchanger and the refrigerant naturally flows. When a so-called liquid back phenomenon in which the circulation stops occurs, a control device is required to prevent this, which is complicated not only in terms of price but also in the control system.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention separately installs a cold heat source at an upper position of a building and a hot heat source at a lower position of a building, and installs a cold heat source at an upper part of a building during cooling operation. It is an object of the present invention to provide a refrigerant natural circulation type cooling and heating system in which the refrigerant is naturally circulated for both cooling and heating by using a heat source in the lower part of the building during heating operation.

[0006]

DISCLOSURE OF THE INVENTION In a refrigerant natural circulation type cooling and heating system according to the present invention, a cooling heat source for cooling and liquefying a phase-changing refrigerant is installed at a position higher than a fan coil unit installed in each room in a building. A refrigerant liquid carrier pipe and a refrigerant gas carrier pipe are connected between the cold heat source and the fan coil unit to form a closed circuit in which the refrigerant circulates, and the refrigerant heat-exchanged by the cold heat source is supplied to the fan coil unit. In a refrigerant natural circulation type cooling system for cooling the room, a heat source is installed at a position lower than a fan coil unit installed in each room in the building, and the lower ends of the refrigerant liquid carrier pipe and the refrigerant gas carrier pipe are heated to the same temperature. Supply the refrigerant that has been heat-exchanged by the heat source to the fan coil unit during heating operation, shuts off the refrigerant path to the heat source during cooling operation, and cools during heating operation. It is characterized in that so as to block the path of refrigerant to.

[0007]

In the cooling operation, the refrigerant is cooled by the upper cooling heat source, and the refrigerant is returned to the cold heat source by the pressure difference due to the phase change from the refrigerant liquid to the refrigerant gas in the heat exchanger of the fan coil unit, and in the heating operation. The lower heating source heats the refrigerant, and the refrigerant is returned to the heating source by the phase change from the refrigerant gas to the refrigerant liquid in the heat exchanger of the fan coil unit. As a result, the co-refrigerant naturally circulates during cooling and heating.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the system of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the system of the present invention, in which a condenser 1 in an absorption chiller or the like as a cold heat source installed in a machine room on the roof of a building passes through a heat exchanger 11 of the condenser. Cool the refrigerant. 2 is a fan coil unit installed in each room below the absorption refrigerator 1, and 21 is a refrigerant which is automatically closed when the operation of each fan coil unit is stopped and is supplied to the heat exchanger 22. It is preferable to use an auto-return type motor-operated valve that opens the valve body during energization and automatically closes the valve body when the energization is cut off. In the case of a solenoid valve that does not use an auto-return type motor-operated valve, one that can be shared during cooling and heating, and one that can pass both directions of liquid supply and its shutoff during cooling and liquid return and its shutoff during heating are used. Reference numeral 3 denotes a refrigerant liquid carrier pipe that supplies the refrigerant liquid cooled and liquefied in the absorption refrigerator 1 to the heat exchanger of each fan coil unit 2, and 4 passes through the heat exchanger of each fan coil unit 2. A refrigerant gas carrier pipe for returning the vaporized refrigerant gas to the condenser 11 of the absorption refrigerator 1, and electrically operated valves 1a, 1 are provided at both ends of the condenser 1, respectively.
It is connected via b. Reference numeral 5 denotes an evaporator, which is a heat source installed in a machine room in the basement of the building, and heats the heat exchanger 51 in the evaporator directly with a gas burner or the like, or supplies hot water to indirectly heat the heat exchanger 51. The refrigerant liquid passing through the heat exchanger 51 is heated to vaporize the refrigerant. One end of the heat exchanger 51 of the evaporator 5 is connected to the lower end of the refrigerant liquid transfer pipe 3 and the other end is connected to the lower end of the refrigerant gas transfer pipe 4 via electrically operated valves 5a and 5b, respectively. 6 is the motor-operated valve 1a, 1b,
5a, 5b is a control device for controlling the energization of the motors, and the motor-operated valves 1a, 1b are opened and the motor-operated valves 5a, 5b are closed during the cooling operation.
The motor-operated valves 1a, 1b are closed during the heating operation, and the motor-operated valves 5a, 5
Open b to switch between heating and cooling. In the figure, 7 indicates the evaporator 5 by detecting the pressure or temperature of the refrigerant gas during the heating operation.
The sensor 8 for controlling the operation of the evaporator 5 detects whether or not the refrigerant liquid in the heat exchanger 51 of the evaporator 5 is sufficient.
It is a level sensor that controls the operation of the.

When performing the cooling operation, when the changeover switch of the control device 6 is turned on to the cooling side, the electric valves 1a, 1b.
Is opened, the motor operated valves 5a, 5b are closed, and the evaporator 5 for the refrigerant is closed.
Is cut off, the condenser 1 is cooled, and the cooling operation is started. Since the refrigerant in the heat exchanger 11 of the condenser 1 is in a liquefied state when the electric valves 1a and 1b are closed,
While being cooled, it descends in the refrigerant liquid carrier pipe 3 by its own weight,
The heat exchanger 21 of the fan coil units 2 ... 2 located below
21 and is vaporized by heat exchange at the time of passing through and is returned to the condenser 1 through the refrigerant gas carrier pipe 4 and is cooled there again and passed through the refrigerant liquid carrier pipe 3 and the fan coil unit 2 2 heat exchangers 21 to 21 are supplied to the natural circulation cycle to cool each room.

When performing the heating operation, when the changeover switch of the control device 6 is turned on to the heating side, the electric valves 1a, 1b.
Is closed and the path of the refrigerant to the condenser 1 is cut off, the motor operated valves 5a and 5b are opened to open the path of the refrigerant to the evaporator 5, and the evaporator 5 is heated by means to be described later. The operation is started. The refrigerant in the heat exchanger 51 of the evaporator 5 is in a liquefied state when the motor-operated valves 5a and 5b are closed, but the heat exchanger 51 of the evaporator 5 is directly heated by a gas burner or indirectly by hot water. When heated, heat exchanger 5
Since the refrigerant in 1 is heated and vaporized, it passes through the refrigerant gas carrier pipe 4 and passes through the inside of the heat exchangers 21 ... 21 of the fan coil units 2 ... 2, and is liquefied by heat exchange during passage. 2 through the refrigerant liquid carrier pipe 3 to be returned to the evaporator 5 by its own weight, where it is vaporized again and passes through the refrigerant gas carrier pipe 4 and the heat exchanger 21 of the fan coil units 2 ...
A natural circulation cycle is supplied to 21 to heat each room. Refrigerant naturally circulates in each room to cool and heat each room regardless of heating / cooling or heating operation.

When a liquid back phenomenon occurs in the heat exchanger of the fan coil unit during the cooling operation, the natural circulation of the refrigerant is stopped and the temperature of the condenser 1 is rapidly lowered.
A temperature sensor provided inside detects the suddenly lowered temperature and sends a signal to the control device 6 so that the heating operation can be immediately switched to.

When switching to the heating operation, the refrigerant gas from the evaporator 5 does not evaporate or evaporate the refrigerant liquid accumulated in the inside of the refrigerant gas carrier pipe and is pushed back to the absorption refrigerating machine 1 side. The inside of the refrigerant gas carrier pipe is in a state of only the refrigerant gas. The liquid back phenomenon can be resolved within a short time by setting a time for this gas only state in a timer in advance and returning to the cooling operation again after the elapse of this time.

In some cases, the upper part of the building needs to be cooled and the lower part of the building needs to be heated depending on the condition of the middle period or the location of the building. The electrically operated valves 5a ', 5a ", 5b', 5b" having the same operation as the electrically operated valves 5a, 5b are respectively interposed to separate the floors requiring cooling and the floors requiring heating by closing the electrically operated valves. , Which can cool the floors above the applicable motorized valve and heat the floors below,
Partial cooling and partial heating can be realized in a plurality of heating / cooling systems as well as one heating / cooling system shown in the figure.

[0014]

According to the refrigerant natural circulation cooling and heating system of the present invention, the cooling and heating sources are separately installed at the upper position of the building and the heating and heating sources are respectively installed at the lower position of the building, and the cooling and heating sources at the upper part of the building are operated during the cooling operation. In the heating operation, the heat source at the bottom of the building is used to naturally circulate the refrigerant for both heating and cooling.Therefore, as in the prior art, the refrigerant passes through the heat exchanger of the fan coil unit during heating operation. Since it does not require a transfer power such as a pump to return the liquefied refrigerant to the heat source, the running cost is low and the pump itself is unnecessary, so a refrigerant tank to prevent the pump from causing cavitation phenomenon is provided. There is no need to provide it, and there is no need to secure extra refrigerant in the tank,
Further, there is no need for a control device such as a float switch for controlling the operation of the pump and another pipe for returning the refrigerant liquid by the pump, and not only the running cost but also the initial cost can be made low. The liquid back phenomenon at that time can be immediately eliminated, and an excellent effect can be obtained not only in cost but also in operation.

In this embodiment, one cooling / heating system has been described, but in a building in which this system is adopted, the system is usually constituted by a plurality of cooling / heating systems, so as shown in FIG. By combining multiple heat sources in one place and supplying hot water in common to these heat sources, the heating operation of all systems can be centrally managed in one place, and maintenance and inspection are easy. Also in terms of surface, it is possible to exert an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a system of the present invention.

FIG. 2 is a schematic explanatory diagram showing a management state of a plurality of heat sources.

FIG. 3 is a schematic explanatory diagram of a conventional system.

[Explanation of symbols]

 1 Condenser 2 Fan coil unit 3 Refrigerant liquid carrier pipe 4 Refrigerant gas carrier pipe 5 Evaporator 6 Controller

Claims (1)

[Claims] 1. A cold heat source for cooling and liquefying a phase-change refrigerant is installed at a position higher than a fan coil unit installed in each room in a building, and a refrigerant liquid is provided between the cold heat source and the fan coil unit. In a refrigerant natural circulation type cooling system that cools each room by supplying a fan coil unit with a refrigerant that has been heat-exchanged by a cold heat source to form a closed circuit in which the refrigerant is circulated by connecting with a carrier pipe and a refrigerant gas carrier pipe, A heat source is installed at a position lower than the fan coil unit installed in each room in the building, and the lower ends of the refrigerant liquid transfer pipe and the refrigerant gas transfer pipe are communicated with each other through the same heat source to heat the heat source during heating operation. The heat exchanged refrigerant is supplied to the fan coil unit, the refrigerant path to the heat source is blocked during the cooling operation, and the refrigerant path to the cold source is blocked during the heating operation. Refrigerant natural circulation cooling and heating system.