JPH0340307B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of effectively utilizing the thermal output of an absorption heat pump device.

First, the principle of an absorption heat pump will be explained with reference to FIG. 1 is a generator, and when heating is performed by burning gas etc. with a burner 2, refrigerant vapor is generated from a solution 3 in which the refrigerant is absorbed into an absorption liquid, and the refrigerant vapor is passed through a pipe 4 to a condenser provided in a heated space 5. 6, and the heat of condensation is used by the wind generated by the fan 7 to warm the indoor air. The liquefied refrigerant condensed here goes out of the space to be heated 5 through a pipe 8, and is sent through a pressure reducing valve 9 to an evaporator 10 provided outdoors. If the evaporation temperature is Te and the outside air temperature is Tam, then if Te<Tam, the refrigerant evaporates in the evaporator 10 by extracting heat from the outside air.

Air is forcibly sent to the evaporator 10 by a fan 11 so as to improve heat exchange with the outside air.

The evaporated refrigerant vapor passes through the pipe 12 to the absorber 13
flows into. On the other hand, refrigerant vapor is released in the generator 1 to the absorber 13, and the high-temperature dilute solution with reduced refrigerant content passes through the pipe 14 and the heat exchanger 15, and exchanges heat with the concentrated solution described below. The temperature is lowered and the water passes through the flow rate regulating valve 16 and is poured into the absorber 13.

A cooling water pipe 17 is also provided in the absorber 13 to cool the solution. The dilute solution poured into the absorber 13 absorbs the refrigerant vapor and becomes a concentrated solution, but at this time a large amount of absorbed heat is generated. This absorbed heat is taken away by the water flowing through the cooling water pipe 17. That is, the water leaves the absorber 13 heated. This hot water passes through a pipe 18 to a radiator 1 installed in the heated space 5.
9, the air generated by the fan 20 gives heat to the indoor air, and the water is sent to the cooled pipe 2.
1. The water reaches the absorber 13 via the water pump 22.

On the other hand, the concentrated solution that absorbs refrigerant vapor in the absorber and is cooled with cooling water passes through the pipe 23, is pressurized by the solution pump 24, and is heat exchanged with the high-temperature dilute solution in the heat exchanger 15. It is heated and fed into the generator 1 to complete the cycle.

As is clear from the above explanation, in the absorption heat pump, in addition to the heat given by the burner 2 in the generator 1, the heat given from the outside air in the evaporator 10 is transferred to the condenser 6 and the heat exchanger 19.
Since the heating output is the sum of these two, and the only paid heat input is the heat input of the burner 2, the coefficient of performance, that is, the heating output, is the heating input. The value divided by is greater than 1, and it is attracting a lot of attention today as an energy-saving device.

There are two types of heat output of this absorption heat pump device: heat of condensation in the condenser and heat of absorption in the absorber. Although they are the same thermal energy, not only the temperature obtained is different, but also the heat of condensation There is an essential difference in that the generation of heat occurs over a certain temperature range, and unless this difference is carefully considered and the generated heat is not utilized, the overall performance will deteriorate and effective heat utilization will not be achieved. do not have.

To explain in more detail, the coefficient of performance of an absorption heat pump improves as the condensation temperature decreases, but from the perspective of utilizing the generated heat, heat at a very low temperature is not useful. To give specific numbers, a good condensing temperature is around 45℃, and 50℃ can be considered the highest limit. Therefore, if you use this to heat water, etc., the temperature of the water you can raise is at most 45℃.
It is considered to be a rank. If this heat is used directly to heat a room, the required room temperature is 20-25℃, which is considerably lower than this heat source temperature, so the condensation temperature of 45-50℃ is a heat source that can be fully used. If it were to be used, the resulting water temperature would be 40-45°C, which is too low. In addition, when this hot water is used for heating, the temperature of the hot water is limited to 30 to 35 degrees Celsius considering the room temperature, and although the temperature difference is small, the amount of heat generated accounts for about 40% of the total amount of heat. There is.

On the other hand, the generation of absorbed heat in the absorber depends on the cycle setting conditions, but it occurs continuously in the range of about 45 to 90 degrees Celsius, and the lower the minimum temperature, the better the coefficient of performance of the absorption heat pump cycle. do. Therefore, the inlet temperature of the liquid cooling the absorber is 40
℃ or less is required.

The outlet temperature depends on the flow rate of the coolant, but it can be 60℃ or higher. Also, the amount of heat generated accounts for about 60% of the total calorific value.

If you want to use this warmed liquid for heating as is, you should choose an indoor radiator that will keep the return temperature below 40℃.

The heat generated by the absorber has a relatively high temperature, so it is convenient to use it as is for heating.

In the conventional absorption heat pump, as shown in Fig. 2, both the condenser and the absorber are liquid cooled, and the cooling pipe 26 of the condenser 25 and the cooling pipe 28 of the absorber 27 are connected in series. Then, it is heated in an absorber. When heating with this configuration,
Since the ratio of temperature rise for each heat is the ratio of each output heat amount, the heating return temperature entering the condenser is 35
℃, if the temperature is raised by 5℃ in the condenser, the temperature will rise by 7.5℃ in the absorber, and the liquid temperature at the absorber outlet will be 47.5℃.

The reason why the absorber outlet liquid temperature is so low is because the amount of liquid circulated is too high to extract all the heat from the low condensing temperature, even though the optimum amount of liquid for the absorber is small. It comes from being there. Note that in FIG. 2, 29 is a generator.

Another method, as shown in FIG. 3, is to provide a condenser 32 and a heat exchanger 33 between the absorber cooling liquid and the liquid in the tank in one hot water tank 31. In order to extract heating output from the tank, another heat exchanger 34 must be installed inside the tank, which not only increases the cost but also lowers the temperature. In FIG. 3, 35 is a generator, 36 is an absorber, 37 is an evaporator, and 38 is a faucet for taking out hot water from the hot water storage tank 31.

In this way, the conventional method of transferring the heat output of an absorption heat pump device to a single heat medium and utilizing it has the disadvantage that it cannot be used to take advantage of the characteristics of each heat output.

The present invention is an improvement in which the heat output of such an absorption heat pump device can be utilized by taking advantage of its characteristics.

An embodiment of the present invention will be described below with reference to FIG. In FIG. 4, 39 is a generator;
Solution 54 heated by burner 40 generates refrigerant vapor.

If the valve 55 is now closed and the valve 56 is opened, the refrigerant vapor is condensed in the condenser 58 provided in the hot water storage tank 57 and warms the water in the tank. City water is supplied to this tank via piping 59. Note that 52 is also an indoor condenser.

The condensed refrigerant passes through the expansion valve 60, evaporates in the evaporator 40, and flows into the absorber 41.

On the other hand, the diluted solution that has released the refrigerant in the generator 39 flows into the absorber 41 through the valve 42, absorbs the evaporated refrigerant vapor in the evaporator 40, becomes a concentrated solution, and is pumped into the generator by the solution pump 43. Sent back to 39th.

In the absorber 41, since the refrigerant vapor is absorbed by the solvent in this way, a large amount of heat is generated. This heat is carried away by the liquid flowing back through the cooling tubes 44.
That is, the coolant pumped by the liquid pump 45 is heated and leaves the absorber at a temperature close to 60°C. This liquid is transferred to the second hot water storage tank 4 via piping 46.
7, and the low temperature liquid at the bottom flows into the absorber 4.
It is attributed to 1.

When using this heat for heating, the second hot water storage tank 4
From the upper part of the hot water tank 7, the liquid is sent to the indoor radiator 50 by a pipe 48 and a pump 49, and the cooled liquid is returned to the lower part of the hot water storage tank 47.

The liquid that transports this absorbed heat is usually water, but
Additives are added to prevent freezing and corrosion, so it cannot be used directly as hot water.

When using an absorption heat pump for heating,
Indoor radiator 50 and heat exchange section 44 in absorber 41
The advantage of providing the hot water storage tank 47 as in this embodiment across the reciprocating pipeline between the closed circuits connecting the two is that the absorption heat pump can be turned on and off frequently depending on the load of the space to be heated. It has a feature that allows you to control the heating output.

On the other hand, since the first hot water storage tank 57 stores clean water heated to nearly 40°C, the second hot water storage tank 4
By taking out the water from the hot water storage tank 57 through the heat exchanger 51 provided at the hot water supply outlet 5, the 40°C water is further heated and is turned into hot water almost suitable for hot water supply.
It can be supplied from 3. Although water is supplied to the first hot water tank 57, there is no problem in principle if other liquids are supplied. In this case, the hot water storage tank 57 is a liquid storage tank. When a liquid other than water is used, the water heat exchanged with the liquid is led to the heat exchanger 51 of the second liquid storage tank 47.

Here, the effects of the present invention will be further described while comparing with the conventional example. The configuration of the conventional example described above has the disadvantage that hot water supply or heating cannot be performed at a sufficient temperature, or the condenser in this embodiment is provided in the second hot water storage tank and the first hot water storage tank is omitted. In this case, even the lowest temperature part of the hot water storage tank is at most the indoor radiator return water temperature, which is about 40°C, and there is a risk that the condensation temperature will rise too much, making it impossible to fully utilize the condensation heat.

Since the liquid in this hot water storage tank cannot be used directly for hot water supply, a heat exchanger 51 is installed in this hot water storage tank.
This method cannot be expected to produce high hot water temperature. On the other hand, even if the temperature of the city water flowing into this heat exchanger is sufficiently low, the temperature at the lowest temperature part of the hot water storage tank may not drop much, or it may be possible to lower it to near the city water temperature by installing a very large heat exchanger. In this case, the temperature of the water returning to the absorber becomes too low, and the evaporation temperature of the refrigerant in the evaporator becomes too low, increasing the risk of freezing.

In any case, the temperature of the low-temperature part of the hot water storage tank drops only when hot water is being used, and as in this example, the condenser is placed in the first heat collection tank filled with low-temperature city water. Compared to the case where the heat of condensation is provided, the disadvantage is that the heat of condensation cannot be fully utilized.

As described in detail above, in the present invention, the heat output of an absorption heat pump is in two places: the condenser and the absorber, and although there is no problem with the condenser being cooled at a low temperature, the temperature that can be obtained is at most 40°C. ℃, and the absorption heat is about 60℃, but considering that it is not good if the water temperature returned to the absorber is too low because it lowers the evaporation temperature too much, the first liquid storage tank is used to exchange heat with the condenser. By providing a second liquid storage tank having a heat exchanger that stores the coolant of the absorber and exchanges heat with the hot water from the first hot water storage tank, the heat output can be increased by taking advantage of the characteristics of the absorption heat pump. However, it can be used effectively.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of an absorption heat pump, Figs. 2 and 3 are block diagrams of heat output extraction in a conventional absorption heat pump device, and Fig. 4 is a block diagram of a heat pump device according to an embodiment of the present invention. It is. 39... generator, 41... absorber, 47... liquid storage tank, 51... heat exchanger, 57... hot water storage tank, 58... condenser.

Claims (1)

[Claims] 1. A first liquid storage tank forming an absorption heat pump cycle comprising at least a generator, an evaporator, a liquid-cooled condenser, and an absorber, and storing a liquid for cooling the condenser. By separately providing a second liquid storage tank for storing a liquid for cooling the absorber and the absorber, the heat output of each is stored separately, and a heat exchanger is provided in the second heat storage tank, An absorption heat pump device in which a first liquid storage tank is provided with a cooling liquid supply end, and the liquid in the first liquid storage tank is taken out through the heat exchanger. 2. The absorption heat pump device according to claim 2, wherein the liquid that cools the condenser and is stored in the first liquid storage tank is water supplied for hot water supply.