JPH0829011A - Heat pump system - Google Patents

Abstract

PURPOSE:To reduce the initial cost during a cooling operation and carry out a high head operation during the heating operation by a method wherein a system is operated under one set of two heat pumps is applied, and a piping system is comprised of a first heat pump and a second heat pump for use in circulating water at the midway part of the piping during the cooling operation and the heating operation. CONSTITUTION:The piping system is made such that cold water is circulated in series from an evaporator 2 of a first heat pump 29 to an evaporator 10 of a second heat pump 30 during the cooling operation and further a cooling water is circulated in series from a condensor 1 of the second heat pump 30 to a condensor 9 of the first heat pump 29. In turn, during the heating operation, water of heat source is circulated to the evaporator 2 of the first heat pump 29 and hot water is circulated to the condensor 9 of the second heat pump 30 and then the condensor 9 of the first heat pump 29 and the evaporator 10 of the second heat pump 30 are formed of a closed circuit. Then, these first and second heat pumps 29 and 30 are arranged in the midway part of the pipe. With such an arrangement as mentioned above, the initial cost during the cooling operation can be reduced and a high head operation during the heating operation can be carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump system, which can take out high temperature water during heating,
The present invention relates to a heat pump system that enables highly efficient operation during heating and is suitable for energy saving.

[0002]

2. Description of the Related Art Generally, in the operation of a water-cooled heat pump,
Since high-temperature water is taken out during heating, the condensing temperature of the refrigerant becomes high, the temperature difference from the evaporation temperature becomes large, and the required heat insulating head in the compressor becomes larger than that in cooling.

As a result, when a compressor is designed under a heating condition with a large adiabatic head, a low head operation is performed with respect to the design point during cooling, resulting in a significant decrease in efficiency.

Further, as one means of the system for solving the above-mentioned problems, there is a method as shown in FIG. In the figure, a heat pump 114 is connected in series with the compressors 103 and 105, the condenser 101, the expansion valve 107, and the evaporator 102 in this order so as to form a closed circuit, and a pipe 111 and a compressor for conducting the refrigerant. It is configured by driving machines 104 and 106 for driving 103 and 105. In this system, the piping system is switched by valves 108, 109, 110 for the compressor 103 designed under the cooling condition only during the heating operation, the booster compressor 105 is added, and two compressors are connected in series. This is a method that enables high head operation. This method is a well-known technique in this technical field, but since the booster compressor cannot operate during cooling, operating efficiency is not preferable from the viewpoint of system configuration.

A known example of a system for supplying high-temperature heat energy by high head operation is disclosed in Japanese Patent Laid-Open No. 61-110849, but there is no specific description of the operation method during cooling.

[0006]

According to the heat pump system constructed as in the prior art, the booster compressor provided for the high head during heating is not operated during cooling, so the operating efficiency of the system is low. Is not preferable.
That is, in the cooling operation, the cooling energy ratio output to the system initial cost and equipment capacity is small.

An object of the present invention is to perform a high head operation during heating, that is, a heat pump system and an operation capable of taking out high-temperature water without deteriorating the initial cost during cooling operation and the ratio of cold energy output to the installed capacity. To provide a method.

[0008]

In order to achieve the above object, the present invention provides a system in which two heat pumps are operated as a set, and during cooling, cold water is evaporated from the evaporator of the first heat pump to the evaporator of the second heat pump. Piping system so that the cooling water circulates in series to the condenser, and the cooling water circulates in series from the condenser of the second heat pump to the condenser of the first heat pump. In order to circulate to the evaporator and to circulate hot water to the condenser of the second heat pump, the condenser of the first heat pump and the evaporator of the second heat pump are formed in a closed circuit, and water is supplied in the middle of the pipe. By configuring with a piping system equipped with a pump for circulation, by operating two heat pumps during cooling, the operating rate as a system is improved, and during heating, after heating with the first heat pump, It made it possible to take out the high-temperature hot water by re heating in two heat pumps.

[0009]

According to the structure of the present invention, during cooling, the cold water is circulated in series from the first heat pump evaporator to the evaporator of the second heat pump, so that the cold water is cooled in two stages by the two evaporators. It On the contrary, the cooling water circulates from the condenser of the second heat pump to the condenser of the first heat pump in series, so that the cooling water is heated in two stages by the two condensers.

On the other hand, during heating, heat is taken from the hot water heated by the condenser of the first heat pump by the evaporator of the second heat pump, and hot water is obtained by the condenser of the second heat pump. The heat energy of the refrigerant heated by the first heat pump is used as heating for relaying with water once, and the second heat pump further heats up to obtain hot water.

Therefore, as shown in FIG. 3, it is possible to reduce the difference between the condensation temperature and the evaporation temperature as compared with the case where cooling is performed under the same chilled water cooling water condition by one refrigerator during cooling. That is, the power required for freezing can be saved. Further, as compared with the conventional method, since two compressors are operated at the time of cooling and heating, it is possible to increase the cooling energy with respect to the equipment capacity.

Therefore, it is possible to perform high head operation during heating, that is, to take out high-temperature water, without impairing the initial cost during cooling operation and the ratio of cold energy output to the equipment capacity.

[0013]

FIG. 1 shows a heat pump system according to an embodiment of the present invention.

In the figure, the second heat hoop 29 is the compressor 3
The condenser 1, the expansion valve 5, and the evaporator 2 are connected in series in this order so as to form a closed circuit, and 4 is a driving device for driving the compressor 3.

Similarly, the first heat pump 30 is also composed of a compressor 11, a condenser 9, an expansion valve 13, an evaporator 10 and a driver 12.

On the other hand, on the water side, the switching valves 18, 19,
20, 21, 22, 23, 24, 25, 26 and pump 1
7 and the pipes 27 and 28, which are closed in the cooling time so that the valves 18, 21, 22 and 25 are closed and cold water is circulated in series from the evaporator of the first heat pump to the evaporator of the second heat pump. And cooling water is circulated in series from the condenser of the second heat pump to the condenser of the first heat pump. Therefore, heat exchange is performed stepwise by the first heat pump and the second heat pump.When the load is full, two heat pumps can be operated, and when the load is low, only one can be operated, which reduces the efficiency of the compressor. Instead, the capacity can be controlled in a wide range. In addition, when the two compressors are operated at full load, the amount of extracted cold heat with respect to the equipment capacity can be increased as compared with the conventional technology.

Next, the heating operation will be described. During heating, the valves 19, 20, 24 and 26 are closed, and heat source water is circulated to the evaporator of the first heat pump and hot water is circulated to the condenser of the second heat pump. Water is circulated in a closed circuit by the pump 17 between the condenser of the first heat pump and the evaporator of the second heat pump. Therefore, the heat released by the condenser of the heat pump 2 is recovered by the evaporator of the heat pump 1, and this heat is used as the heat of evaporation in the heat pump 1 and constitutes a refrigeration cycle. In this case, if the heat vaporizing temperature of the heat pump 1 and the condensing temperature of the heat pump 2 are set so that the required heat insulating heads of the compressor of the heat pump 1 and the compressor of the heat pump 2 are the same as those in the cooling time, the cooling time can be reduced. The co-compressor at the time of heating can be operated with high efficiency, and the hot water taken out by the heat of condensation of the heat pump 1 can obtain the same temperature level as the cycle when the booster compressor is added.

As described above, the refrigerant system remains the same as the prior art,
By combining two heat pumps and devising a system on the water side, it is possible to take out high temperature water during heating and to operate the compressor with high efficiency through cooling and heating.

[0019]

According to the present invention, a system in which two heat pumps are operated as a set is provided, and during cooling, cold water is circulated in series from the evaporator of the first heat pump to the evaporator of the second heat pump, In addition, the cooling water has a piping system that circulates in series from the condenser of the second heat pump to the condenser of the first heat pump, and during heating, the heat source water circulates to the evaporator of the first heat pump, The hot water is circulated to the condenser of the second heat pump, and the condenser of the first heat pump and the evaporator of the second heat pump are formed in a closed circuit,
By constructing a piping system equipped with a pump for circulating water in the middle of the piping, high head operation during heating can be performed without impairing the initial cost during cooling operation and the ratio of cold energy output to the installed capacity. That is, high temperature water can be taken out.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of a heat pump system of the present invention.

FIG. 2 is a system diagram showing an example of a conventional heat pump system.

FIG. 3 is an explanatory diagram of a condensation temperature and an evaporation temperature.

[Explanation of symbols]

1, 9 ... Condenser, 2, 10 ... Evaporator, 3, 11 ... Compressor, 4, 12 ... Drive machine, 5, 13 ... Expansion valve, 6, 14 ...
Refrigerant piping, 7, 8, 15, 16, 27, 28 ... Water piping,
18, 19, 20, 21, 22, 23, 24, 25, 2
6 ... Switching valve, 17 ... Pump, 29, 30 ... Heat pump.

Claims (1)

[Claims] 1. A compressor, a condenser, an expansion valve and an evaporator are connected in series in this order so as to form a closed circuit, a pipe for conducting a refrigerant, and a drive for driving the compressor. And a heat pump equipped with a control device for controlling the operation of the compressor, a system in which the heat pumps are operated as a set of two, and during cooling, cold water is from the evaporator of the first heat pump to the evaporator of the second heat pump. In order to circulate in series, cooling water is a piping system in which cooling water is circulated in series from the condenser of the second heat pump to the condenser of the first heat pump. Heat source water is passed through the evaporator of the one heat pump, hot water is circulated to the condenser of the second heat pump, and the condenser of the first heat pump and the evaporator of the second heat pump are formed in a closed circuit. Heat pump system, characterized in that a such piping system, it is provided with a pump for circulating water in the middle of the pipe.