JP3433306B2 - Improvement of cooling operation in heat medium circulation type air conditioning system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger (cooling / heating energy supply source) provided at an upper part of a building and an air conditioner (cooling / heating energy) provided inside the building. A heating medium (energy medium) circulating air-conditioning system for cooling and heating by connecting a pipe carrying a liquid heat medium (liquid energy medium) and a pipe carrying a gaseous heat medium (gas energy medium) Regarding system improvement. That is, when the heating operation is performed by the above system, the heating medium (gasification heating medium) is sent from the heat exchanger to the air conditioner and liquefied and returned, because the purpose is to heat the air conditioning object. When the cooling operation is performed and cooling is performed, a cycle of sending a cooling medium (liquid heating medium) from the heat exchanger to the air conditioner and returning it to gasification is performed. Hereinafter, in the description of the present invention, when the meaning is clear, the heating medium may be referred to as a heating medium, and the cooling medium may be referred to as a refrigerant. [0003] First, a heat medium circulation type air conditioning system will be described with reference to FIG. In FIG. 1, A is a building to be air-conditioned, E is a heat exchanger for cooling and heating provided on the roof, and a heat exchange coil E1 is provided therein.
And so on. B1 is a heating medium pressure adjusting tank, the description of which will be described later. A2, A1, Au are on the second floor of the building, 1
The floor and the basement may be assumed. The air conditioners (FCU) provided on each floor of A2 and A1 are 2a, 2b, 1a, 1
b. B2 is a heat medium tank, the description of which will be described later. P is a heat medium transport pump provided on the lowest floor Au. [0004] Explaining the piping, the range indicated by the symbol C and indicated by the double line of the solid line and the dotted line is the circulation (cycle) range of the gaseous heat medium (heat medium gas), which is the same during heating and cooling. Absent. However, as will be described later, the transport direction is indicated by an arrow and "cold" in the cooling direction, and is indicated by an arrow and "warm".
Is the direction at the time of heating. The solid line (1
The range of (book) is the piping of the liquid heat medium (heat medium liquid), and the transport direction is indicated by the arrow and "cool" during cooling, and the arrow and the "
The direction of heating is indicated by "warm." However, the piping range through which the heating medium passes differs between cooling and heating, but the details will be described later. Next, referring to FIG. The circulation (cycle) range of the heat transfer fluid during heating is indicated by a double solid line.
The switching valves S2 and S1 included in the above are closed, and the heat medium gas heated and vaporized by the coil E1 of the heat exchanger E passes through the pipe C to the air conditioners (FCU) 2a, 2b, 1a and 1b,
After being cooled and liquefied in the air conditioner, it exits the air conditioner and accumulates in the tank B2. The pump P returns from the tank B2 to the coil E1 via the check valve V1. The pipe branches just before the heat exchanger E and one branches to the pressure regulating tank B1. Next, the operation of the system during cooling will be described with reference to FIG. The circulation range of the heating medium during cooling is 2
This is indicated by a heavy solid line, which is different from that during heating. That is, the pipe D
, The heat transfer fluid cooled by the coil E1 bends at the points D1 and D2 of the pipe D after exiting the coil E1, passes through the switching valves S2 and S1, and passes through the air conditioner 2.
a, 2b, 1a, and 1b, gasification and heat exchange, and then return to the coil E1 through the pipe C. When the cooling load fluctuates during this cooling operation, or when a heat medium (refrigerant) flow control device (automatic expansion valve, temperature expansion valve, etc., hereinafter represented by "expansion valve") provided in the air conditioner is used. If the operation is not fast enough, the heat medium (refrigerant) liquid may remain in a liquid state without being completely vaporized (gasified) immediately after the expansion valve, and may remain in a part of the gas. This is called "liquid back". The mixing or remaining of the heat medium (refrigerant) liquid in the liquid back phenomenon shuts off the gas flow in the horizontal drawing pipe or the pipe on the lower floor of the air-conditioning, so that the natural gas flows. The return of the gasification heat medium (refrigerant) by circulation cannot be achieved, which causes an obstacle to the cooling operation. [0008] The present invention relates to a countermeasure in the event of a liquid back phenomenon, which will be described with reference to FIG. 3. The present invention relates to measures taken from the air conditioners 2 a, 2 b, 1 a, 1 b. Immediately after, at a pipe position where the residual refrigerant liquid is easily collected, that is, at a point f1 in the drawing, a new branch pipe F having a check valve V2 interposed is formed in the pipe D to guide the residual liquid to the tank B2. At this time, gas-liquid separation is carried out.) In a state where the liquid is appropriately collected in the tank B2, a part of the pipe D is passed through the pipe D using the pump P, that is, a part of the pipe for handling the heating medium for heating. The refrigerant flowing from the point D2, which is the turning point to the lowest floor A1 of the air conditioning target area, to the air conditioners 1a and 1b through the switching valve S1 (open) as indicated by the bent arrow By mixing with the liquid, the trouble is preferably avoided.
In the drawing, the point f1 corresponds to the air conditioners 2a, 2a on the floors A2 and A1.
The branch point of the pipe is shown at one point (f1) as a suitable place for collecting and collecting the residual refrigerant liquid in the liquid bags from b, 1a, and 1b, but this is merely an example. A plurality of pipe branches for collecting the liquid bag may be provided at each floor of the target area or in accordance with the installation area of the air conditioner. That is, the outline of the present invention is as follows. A heat medium circulation type air conditioner that cools and heats by connecting a heat exchanger installed at the top of the building and an air conditioner installed inside the building with pipes that transport liquid heat medium and pipes that transport gas heat medium In the system, in the middle of the return pipe of the gasification heat medium generated in the air conditioner during cooling to the heat exchanger, a branch pipe to the transfer device for the liquid heat medium used during heating is provided, and the gasification heat medium is gasified. The present invention relates to an improvement characterized in that when a heat medium liquid not included is contained, gas-liquid is separated, and the heat medium liquid that has not been gasified is returned to a pipe to an air conditioner in the transfer device. Further, the present invention will be broadened as follows. In a heat medium circulating air-conditioning system that performs cooling and heating by connecting a cooling medium heating energy supply source and the energy consuming terminal with a pipe that conveys a liquid heat medium and a pipe that conveys a gaseous heat medium, the energy consuming terminal is used for cooling. A branch pipe is provided in the middle of the pipe for returning the gasification heat medium generated in the above to the energy supply source, and when the gasification heat medium contains a heat medium liquid that is not gasified, the gas-liquid separation is performed. The invention relates to an improvement characterized in that the minute is returned to the cooling cycle. According to the present invention, the disadvantages of the two-pipe heat medium natural circulation air conditioning system during the cooling operation are eliminated. Further, as can be understood from the above description, the cooling energy supply source is not limited to the heat exchanger described in the embodiment, but may be a heat pump type cold heat generation source or a chiller unit. The heat medium (energy medium) of the present invention may be used for heating (heating) and for cooling (cooling), and different medium materials or the same material may be used. Good. In short, liquid → gas,
It is advantageous to use the latent heat of the gas-to-liquid phase change. [0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an air conditioning system for a building having a heat exchanger at the top of the building and performing heating and cooling by a two-tube heat medium circulation system. FIG. 2 is a diagram illustrating a circulation path of a heat medium when a heating operation is performed in the air conditioning system of FIG. 1; FIG. 3 illustrates a circulation path of a heat medium when performing a cooling operation in the air conditioning system of FIG. 1, and illustrates an embodiment of the present invention. [Description of Signs] A: Buildings B1, B2 to be air-conditioned: Heating medium storage tank C: Piping indicating circulation range of gasification heating medium D: Piping indicating circulation range of liquid heating medium E: Heat exchanger E1: Heat Exchanger coil F: piping part for the present invention P: pumps S1, S2: switching valves V1, V2: check valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-160239 (JP, A) JP-A-5-39963 (JP, A) JP-A-4-121536 (JP, A) JP-A-63- 105368 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F24F 5/00

Claims (1)

(1) A liquid heating medium is transported between a cooling / heating energy supply source (E) provided at an upper position of a building and a cooling / heating energy consumption terminal (FCU) provided inside the building. Pipe (D) and the pipe (C) that transports the gaseous heat medium,
In a heating medium circulation type air conditioning system that performs cooling and heating, a gasification heating medium generated at an energy consumption terminal (FCU) during cooling is returned to an energy supply source (E) in the middle of a horizontal drawing pipe.
When a down branch pipe (F) is provided and the gasification heat medium contains a medium liquid that is not gasified, the heating heat medium provided at the lower part of the building, which is further lower than the energy consumption terminal (FCU). An apparatus characterized in that a medium liquid is collected in a tank (B2), gas-liquid is separated, and the liquid is returned to a cooling cycle by a pump (P).