JPS6312231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat utilization device based on the principle of an absorption heat pump, and particularly to a device having a hot water supply function.

Configuration of conventional example and its problems 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 is sent to a radiator 19 provided in the heated space 5 through a pipe 18, and heat is given to the indoor air by the wind generated by a fan 20, and the water is cooled by a pipe 21, It returns to 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 value divided by the input 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 The essential difference is that absorption heat is generated at a certain temperature, while absorbed heat is generated over a certain temperature range.If we do not carefully consider this difference and utilize the generated heat, the overall Performance is degraded and effective heat utilization cannot be achieved.

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 reach 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 occurs continuously in the range of 45 to 60℃, depending on the cycle setting conditions, 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.

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. In FIG. 2, 29 is a generator, and 30 is an evaporator.

Therefore, in order to effectively utilize an absorption heat pump, when using it for heating, it is preferable to have the condenser directly exchange heat with the air in the space to be heated, and only the heat from the absorber is transferred as hot water.

When using this for hot water supply, a method has been proposed in which condensation heat and absorption heat are stored in a hot water tank using separate water circuits, as shown in FIG. That is, in FIG. 3, 39 is a generator, and the solution 54 heated by the 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 61, and flows into the absorber 41.

On the other hand, the dilute 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 61, 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 picked out by the liquid flowing back through cooling tube 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.

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 at the hot water supply outlet 5.
It can be supplied from 3. In this way, the heat output of an absorption heat pump comes from two places: the condenser and the absorber, and while there is no problem with the condenser being cooled at a low temperature, the temperature that can be obtained is at most about 40℃; The temperature 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 that exchanges heat with the condenser and the coolant of the absorber are By providing a second hot water storage tank having a heat exchanger that exchanges heat with hot water from the first hot water storage tank, the characteristics of an absorption heat pump can be utilized to effectively utilize its heat output.

A problem with this method is that the temperature of the water supplied for hot water supply varies significantly depending on the season.

In other words, the temperature of tap water can reach nearly 30°C in the summer, but it can drop to nearly 0°C in the winter.

Therefore, the amount of heat that must be input until the first hot water storage tank, which stores the heat of condensation, reaches 40°C is four times different when the supplied water temperature is 0°C than when it is 30°C. Therefore, if the above-mentioned first hot water storage tank is always operated until it reaches 40℃, when the supply water temperature is high, the second hot water storage tank will only warm up the upper layer and will stop without raising the temperature to the lower layer. . On the other hand, when the supply water temperature is low, the operation time becomes longer, and the water temperature in the second hot water storage tank becomes the absorber outlet water temperature as a whole, which prevents the absorber from being cooled and causes problems in the operation of the cycle.

Purpose of the invention The purpose of the present invention is to determine the boiling state of an absorption heat pump hot water heater equipped with a two-tank hot water storage tank,
This provides a rational device for automatically stopping operation.

Structure of the Invention The present invention provides for adjusting the temperature of the liquid flowing back to the condenser and absorber from a first liquid storage tank heated by condensation heat and a second liquid storage tank heated by absorption heat, respectively. It is detected at the bottom of the liquid storage tank or in the pipes between the liquid storage tank and each cooling water inlet, and the operation of the heat pump device is stopped when one of them reaches a predetermined temperature for each. .

In this case, the water temperature obtained by absorption heat can be made higher than the water temperature obtained by condensation heat, and since such usage takes advantage of the features of the absorption type, it is possible to make the water temperature obtained by condensation heat higher than the water temperature obtained by condensation heat. It is better to set the temperature for heat lower than that for absorbed heat.

DESCRIPTION OF EMBODIMENTS The structure of an absorption heat pump hot water heater which is an embodiment of the present invention will be described with reference to FIG. 4.
Since the basic configuration of FIG. 4 is almost the same as that of FIG. 3, the same components are given the same numbers. In the case of FIG. 3, a condenser 58 is provided at the bottom of the first hot water storage tank 57, but in this embodiment, a double pipe condenser 38 is provided separately, and the water pump 33 is used to control the first hot water storage tank 57. The water in the lower part of the tank 57 was sent to the double pipe condenser, warmed by the heat of condensation, and returned to the upper part of the tank. Temperature detectors 36 and 37 are provided in the middle of piping from the bottoms of the second hot water storage tank 47 and the first hot water storage tank 57 to the absorber and the condenser, respectively, to measure the respective supplied water temperatures. This is compared with a temperature measuring device and a reference temperature in a comparator 35, and when either of them exceeds the respective reference temperature, an electromagnetic switch 34 is connected to the power supply circuit.
The operation of the solution pump 43 and the like and the combustion of the burner 40 are stopped to bring the entire system into a stopped state.

In this embodiment, the temperature detector is provided in the pipe that takes out water from the hot water storage tank, but it may also be provided at the bottom of the hot water storage tank. The actual set temperatures are, for example, condenser inlet water temperature 35℃, absorber inlet water temperature 50℃.
It is best to keep it at around ℃. Also, it is preferable that the volumes of the first hot water storage tank and the second hot water storage tank be approximately the same, or that the second hot water storage tank should have a slightly larger capacity, for example, at a ratio of 4:6.

The ratio of generation of condensation heat to absorption heat is approximately 4:6, but varies depending on outside air conditions. Furthermore, even if the temperature is constant, the temperature of the water supplied to the first hot water tank 57 varies greatly depending on the season.

On the other hand, it is necessary to stop the equipment when the cooling water temperature in the condenser rises too much and the generated refrigerant vapor pressure rises too much, or when the cooling water temperature in the absorber rises too much and the refrigerant evaporation pressure in the evaporator rises. This is a case of too much.

For example, if the condenser is operated until the cooling water temperature reaches 35°C, in the configuration shown in Figure 4, it is the 35°C water in the first hot water storage tank that takes heat from the second hot water storage tank. When the water is completely used up, the water temperature in the second hot water tank will be around 40℃. If the outlet temperature of the absorber cooling water is 55°C, the temperature difference is 15°C.

On the other hand, if the temperature of the water supplied to the first tank is 20°C, and the water is heated to 35°C, the temperature difference is 15°C, and the amount of heat stored in both tanks is considered to be approximately balanced. However, when the water temperature is lower than this, the heat storage capacity of the first hot water storage tank increases. Assuming that the water in the second hot water storage tank is almost stratified, the part of the water with a temperature of 55°C gradually descends in the tank until the entire water reaches 55°C.
℃, the absorber will eventually be cooled to 55℃ and the evaporation pressure will rise rapidly, but the first hot water storage tank will not reach the set temperature yet and will continue to operate.

This is inconvenient because the temperature of the cooling water in the absorber rises too much. Therefore, in order to continue operation,
A portion of the heat generated in the absorber must be discarded so that the absorber cooling water temperature returns to its original temperature.

Conversely, if the equipment is set to stop when the absorber cooling water temperature reaches, say, 50°C, then the supply water temperature is 25°C.
If the temperature is as high as 35°C, the temperature of the first hot water tank will exceed 35°C before the stop signal is issued, and there is a danger that the vapor pressure of the generator refrigerant will become abnormally high.

According to the method of the present invention, when any of the hot water storage tanks becomes thermally full, the operation is automatically stopped, thereby eliminating any waste or danger.

For example, when the water temperature is low, if the second hot water storage tank becomes full and the operation stops, the first hot water storage tank remains at a temperature lower than the set temperature, so the next hot water is taken out and used. At this time, the water temperature in the second hot water storage tank becomes lower than the previous time. Therefore, when the operation is restarted, the amount of heat input until the temperature of the second hot water storage tank reaches the set temperature will have increased compared to the previous time.
When the second hot water storage tank becomes full again in terms of temperature and is stopped, the state of the first hot water storage tank is closer to being full in terms of temperature than when it was stopped last time. By using the control method of the present invention as described above, the balance between the two hot water tanks can be achieved after several repetitions, and when the supply water temperature is low, that is, when the air temperature is also low, the absorber cooling The water inlet temperature is balanced at an appropriately low point, which has the effect of appropriately lowering the evaporation pressure and facilitating the evaporation of the refrigerant at low outside temperatures.

Effects of the Invention As detailed above, when condensation heat and absorption heat are stored in a hot water tank in separate loops, and heat is taken out by connecting two tanks thermally in series, the heat is extracted from each tank by a condenser. or the temperature of the cooling water flow connected to the absorber.
By using a control method that stops the operation of the entire device when the temperature exceeds a predetermined temperature, there is no need to waste part of the heat.
By repeating this process several times, the thermal energy stored in the two tanks gradually becomes balanced, and when the water temperature is low, the evaporation pressure, or evaporation temperature, also decreases, which has the excellent effect of not impairing the heat pump function even at lower temperatures.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of an absorption heat pump device, Fig. 2 is an example of a conventional absorption heating water heater in which the condenser and absorber cooling water pipes are connected in series, and Fig. 3 is the premise of the present invention. Fig. 4 is a block diagram of an absorption heat pump water heater according to an embodiment of the present invention. 33... Water pump, 34... Electromagnetic switch, 35
... Temperature measuring device, 36, 37 ... Temperature detector, 3
8...Water-cooled condenser, 39...Generator, 52...Air-cooled condenser, 41...Absorber, 58...Water-cooled condenser, 57...Hot water storage tank for condensed heat, 47...Hot water storage tank for absorbed heat , 51... Heat exchanger, 59... Water supply pipe, 5
3...Hot water faucet.

Claims (1)

[Claims] 1. An absorption heat pump cycle is formed by at least a generator, a liquid-cooled condenser, an evaporator, and a liquid-cooled absorber, and two types of liquid storage tanks are provided, and a first liquid storage tank is provided with two types of liquid storage tanks. is configured to store heat by storing a liquid that cools the condenser, and a second liquid storage tank stores a liquid that cools the absorber, thereby storing the heat output of each separately. Absorption heat pump hot water supply system that has a control function that stops the operation of the device when at least one of the liquid temperatures flowing back from the liquid storage tank to the condenser or absorber exceeds a predetermined temperature for each. heater. 2. The absorption heat pump hot water supply/heater according to claim 1, wherein the set temperature of the absorber liquid temperature at which the operation is stopped is set higher than the set temperature of the condenser liquid temperature.