JPS602586B2 - Absorption heat pump - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in absorption heat pumps.

Generally, using an absorption refrigeration cycle for air conditioning and also using it as a heat pump for heating is a technology that is attracting attention as a requirement of the times due to the energy saving properties of heat pumps. In this case, ``If operating conditions such as the concentration of the medium and the amount of circulation are not changed, even when a device made under the optimal conditions for cooling, such as the evaporation temperature, is used for heating, it will not work well as a heat pump over a wide range of outside air temperatures.'' In other words, the evaporation temperature is not low enough, so if the outside temperature drops slightly, heat cannot be taken in from the evaporator.On the other hand, when using a heat pump, the concentration condition is such that the evaporation temperature is lowered so that it will work even if the outside temperature is low enough. Not only does this increase the risk of freezing on the evaporator during heating, but the evaporation temperature during heating becomes too low and the coefficient of performance deteriorates.One way to solve this problem is to reduce the number of evaporators. Water that has radiated heat with an indoor heat exchanger is not directly poured into the water, but instead passes through a radiator that exchanges heat with the water before reaching the absorber cooling water inlet, thereby reducing outdoor air turbidity. As a result, the temperature of the absorber cooling water can be lowered, and the minimum temperature of the solution in the absorber is also lowered accordingly.As a result, the evaporation temperature is lowered, so it can be used as a heat pump even when the outside air temperature is quite low. It is considered.

Figure 2 shows the principle of an absorbent skin pump that has undergone such improvements. In this figure, when heating is performed by burning gas or the like with a burner 2 in a tlsonma generator, soot vapor is generated from the solution 3 by absorbing the minatojo into the absorption liquid and flowing into the heated space 6 via piping 4. The heat of condensation condenses in the provided condensing heat shaft and is used to warm the indoor air by the wind generated by the fan hole. The liquefied soot condensed here goes out of the heated space 5 through the piping 8, and is transferred to the pressure reducing valve 9.
After that, it is sent to the evaporator Sugamoko, which is installed outdoors. If the evaporation temperature is Te and the outside temperature is Tam, then Te<T
If it is am, Rei-jo will evaporate inside the evaporator by drawing heat from the outside air. Air is forcibly sent to the evaporator by a fan to improve heat exchange with the outside air.

The evaporated Reijo steam flows into the absorption shock 3 via the piping gun lawn. On the other hand, the t-absorber bone hoe releases cold soot vapor from the generator, and the high-temperature dilute solution with reduced solvent content also passes through 9 heat exchangers after many years of piping and becomes the concentrated solution described below. Through heat exchange, the water temperature is lowered and the liquid is passed through the flow rate regulator turtle, and the water is poured into the eight-pronged absorber. I can do it.

The dilute solution poured into the absorber 13 absorbs the cold soot vapor and becomes a concentrated solution, but at this time a large amount of absorption 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 heated. This hot water is pipe 18
The heat exchanger 19 installed in the heated space 5 is also sent through the air, and the air generated by the fan 281 gives heat to the indoor air, and the water is cooled and sent to the absorber via the piping 21 and the water pump 22. come back to. On the other hand, the concentrated solution that absorbs the medium vapor in the absorber and is cooled with cooling water passes through the pipe 23 ~
The solution is pressurized by the solution pump 24, heated by exchanging heat with a high-temperature dilute solution in the heat exchanger 15, and fed into the generator 1, completing the cycle. As is clear from the above explanation, in the absorption heat pump, in addition to the heat given by the generator and the burner, the heat given from the outside air in the evaporator is used in the condenser 6 and heat exchanger 19 to heat the heated space. Since the heating output is the sum of these two, and the only paid heat input is the heat input of burner 2, the coefficient of performance is the value obtained by dividing the heating output by the heating input. is greater than 1, and it is attracting much attention today as an energy-saving device. Although the function of the heat exchanger 25 was not mentioned in the above explanation, this part is the improved part mentioned at the beginning. As the outside air temperature decreases, the heat dissipated here increases, and the temperature of the water returning to the absorber 13 decreases, which lowers the evaporation temperature accordingly, extending the temperature castle where heat can be taken in from the outside air to the lower temperature side. be able to.

Another problem when using an air-source heat pump when the outside temperature is low is ice formation in the evaporator. This cannot be avoided to some extent if the evaporation temperature is below 0°C. The present invention is based on the above prior invention and aims to improve this point. In other words, as the outside temperature, which is the heat source, falls, the evaporation temperature also falls accordingly, and if it falls below 0°C, ice will form in the evaporator, depending on the humidity of the atmosphere.

However, if the temperature of the air introduced into the evaporator is high, no freezing will occur even if the evaporation temperature is below 000, so if the temperature of the air can be raised even a little, the problem of freezing can be alleviated. By the way, in the improved heat pump mentioned earlier, when the outside temperature drops, the heat exchanger 25
This increases the amount of heat discarded to the outside air, thereby lowering the evaporation temperature, so it is extremely meaningful to utilize the heat discarded in this way. , is a graph showing an example of the difference between the outside air temperature and the evaporation temperature, the absorber inlet water temperature, and the utilization rate of absorbed heat.

As is clear from this graph, the utilization rate of absorbed heat decreases as the outside temperature decreases, and a portion of the heat generated in the absorber is discarded into the air at a rate of (1 - utilization rate). become. For example, if the usage rate is 70%, 30% will be thrown away. On the other hand, the amount of heat required by the evaporator depends on the coefficient of performance of the system, but is about 60 to 70% of the amount of heat generated by the absorber, so the amount of heat that is wasted in the air can be transferred to the evaporator. 'Yo, in the numerical example above, ``About half of the heat required by the evaporator can be covered by the heat discarded earlier.

For example, if the outside temperature at that time was 80°C, but the temperature of the air after passing through the evaporator and giving it heat was -2°C, freezing would be inevitable in this case. However, if half of the required heat is supplied from the heat exchanger 25, the air passing through the heat exchanger 25 and the evaporator 10
If the air passing through is the same, {8o-(-2o)}÷2
=5o After passing through the heat exchanger 25, the temperature of the air will rise. That is, air at 8°C is heated to 13qo. Therefore, if this air is subsequently passed through the evaporator, the temperature will drop by 10 degrees, and it will eventually leave the evaporator at 3 degrees Celsius, so it can be considered that no ice will form in this case. As a configuration for this purpose, the present invention forms an absorption type heat pump cycle with at least a generator, a condenser, an evaporator, and an absorber, and ``uses the head heat of the coolant of the absorber for heating etc.'' In the section where the cooling liquid is returned to the absorber after heat dissipation into the heated space,
A heat exchanger for exchanging heat with outside air is provided, and a means is provided for allowing the air that has undergone heat exchange with the heat exchanger to also pass through the evaporator.

With this configuration, the present invention can prevent freezing by reusing the heat picked up by the absorption heat pump, which allows the evaporation temperature to be automatically changed depending on the outside air by discarding a part of the absorbed heat. The fundamental idea of the present invention is to
Further, one embodiment shown in FIG. 3 will be explained in detail.

In Fig. 3, reference numeral 13 denotes an absorber, into which the dilute solution flows through the valve 16, and the liquefied refrigerant that flows into the evaporator 10 through the expansion valve 9 absorbs heat from the air blown by the fan 11, evaporates, and vaporizes. The cooled soot passes through the pipe 12 to the absorber 1.
The river flows into the river, is absorbed by the dilute solution, becomes a concentrated solution, and flows into pipe 2.
3. The solution is sent to the generator via the solution pump 24.

The absorption heat generated when the refrigerant vapor is absorbed into the dilute solution is given to the water flowing in the absorber cooling water pipe 17, and the hot water passing through the pipe 18 is transferred to the heated space 5. The water is sent to a heat exchanger 19 installed inside, and the air generated by two fans gives heat to the atmosphere, and the water is cooled and passes through piping 21, water pump 22, and heat exchanger 25. It is further cooled, enters the cooling water pipe 17 in the absorber again from the absorber cooling water inlet, and is warmed. Here, air passing through the heat exchanger 25 is blown onto the evaporator 101 by a duct 26 and a fan 11 provided therein. With such a configuration, the heat exchanger 2
In step 5, the heat released into the air is directly recovered in the evaporator, so the temperature of the air exiting the evaporator does not drop much as explained earlier, and the ice formation in the evaporator 10 is alleviated. As detailed above, the present invention further improves the invention of making the evaporation temperature of an absorption heat pump variable depending on the outside air temperature and solves the problem of freezing in the evaporator, and has extremely great practical value. It is something.

[Brief explanation of the drawing]

Figure 1 is a block diagram of an absorption heat pump with variable evaporation temperature depending on the outside temperature. Figures 2a and b are the evaporation temperature, absorber cooling water temperature, and outside air temperature - evaporation of the absorption heat pump shown in Figure 1, respectively. Characteristic diagram showing the relationship between temperature and outside temperature,
FIG. 3 is a characteristic diagram showing the relationship between the heat utilization rate and the outside air temperature, and is a configuration diagram of a heat pump according to an embodiment of the present invention. 5... Heated space, 9... Pressure reducing valve, 10...
・Evaporator, 11, 20...Fan, 12, 21
, 23... Piping " 13... Absorber, 16... Flow rate adjustment valve, 17... Cooling water pipe " 18... Piping, 19... Heat exchanger, 22 ... Pump, 25 ... Heat exchanger, 26 ... Duct. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 An absorption heat pump cycle is formed by a generator, a condenser, an evaporator, and an absorber, and the sensible heat of the coolant of the absorber is used for heating, and the coolant after heat radiation is absorbed into the space to be heated. An absorption heat pump that is provided with a heat exchanger for exchanging heat with outside air in a section where the air is returned to the container, and is provided with means for causing the air that has undergone heat exchange with the heat exchanger to also pass through the evaporator.