JPS6334387B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a solar heating device using a multistage chemical heat pump.

[Technical Background of the Invention] In recent years, attempts have been made to effectively utilize low-temperature heat sources such as waste heat using chemical heat pumps. However, if the temperature difference between the low-temperature heat source and the cooling water is small, the required high temperature may not be obtained by using only one stage of chemical heat pump.

[Means to try to solve problems]

The present invention was developed in response to these circumstances, and uses the concentration difference energy accumulated in a long-term heat storage system as a heat source for a chemical heat pump, and collects solar heat at a low temperature during intermediate seasons such as spring and autumn. By combining this low-temperature heat source with a chemical heat pump, we can effectively utilize mid-season solar heat, which could not be used in the past, and also connect chemical heat pumps in multiple stages. hand,
The present invention aims to raise the temperature to a temperature sufficient for heating loads, etc., and improve energy saving effects.The present invention solves the problems of the conventional technology. Each chemical heat pump is combined in series with the exception of the uppermost evaporator, which is connected to a solar collector.
The absorbers constituting P ₁ to Pn and the next-stage evaporator are integrated adjacent to each other, and the absorption liquid in the absorber and the circulating water in the next-stage evaporator are exchanged with each other by a heat exchanger. In order to make the temperature difference between the two equal or small, a heat transfer tube through which circulating water in the evaporator flows is commonly disposed in the absorber and the evaporator, and the heat transfer tube in the absorber An injection pipe for the absorption liquid in the absorber is provided in the upper part, and an injection pipe part for the circulating water in the heat transfer tube is provided in the upper part of the heat transfer tube disposed in the evaporator, and each of the heat exchangers is , are each connected in parallel to a thermal load via a valve.

〔Example〕

To explain the details of the embodiment of the present invention with reference to the drawings, FIG. 1 shows an example of a heating system using solar heat. , as shown by the thick line, the heat medium collected by the solar heat collector 1 is directly guided to the evaporator 2 that constitutes the chemical heat pump P, without being used for heating load, and is absorbed by the chemical heat pump P. This system heats the heating system 3 and performs heating with a heat load of 4. still,
In this case, if the amount of heat is insufficient, for example, a combustion heat source from a fossil fuel boiler may be supplied to the heating load.

In this way, the present invention connects the chemical heat pumps P in series in a multistage manner without adding a fossil fuel boiler, and uses the low temperature heat source in the intermediate period obtained by the solar heat collector 1 and the accumulated concentration difference energy. Based on this, the temperature is raised sequentially using a chemical heat pump connected in a multi-stage manner, and when the temperature reaches a predetermined value, the temperature is supplied to the heating load.

FIGS. 2 and 3 show the configuration of a multistage chemical heat pump that is the gist of the present invention. The following can be considered to improve the efficiency of multistage chemical heat pumps.

(b) Recover the enthalpy of the absorber effluent through heat exchange with the absorber make-up liquid and evaporator make-up water to reduce heat loss.

(b) Reduce the thermal resistance from adjacent absorbers to heat generators and reduce the temperature difference between adjacent absorbers and evaporators.

The present invention proposes the integrated configuration shown in FIGS. 2 and 3 in order to minimize the thermal resistance from the absorber to the evaporator.

E ₁ , E ₂ , E ₃ ...En shown in Fig. 2 are the evaporators of each stage of chemical heat pumps P ₁ to Pn, respectively, and A ₁ , A ₂ , A ₃
...An are each absorbers. The evaporator E ₁ is a low-temperature heat source obtained from a solar heat collector 1 which is a low-temperature heat source. Specifically, as shown in FIG. 1 and a pipeline 5 circulating therethrough. The steam that has absorbed the latent heat of vaporization generated in this evaporator E ₁ enters the adjacent absorber A ₁ via the pipe 6 shown in FIG. 3, and heats the absorption liquid in this absorber A ₁ . As shown in FIG. 3, the circulating liquid in the evaporator E ₂ integrated with the absorber A ₁ is heated through the heat exchanger tube 7 that is circulated in the absorber A ₁ and the evaporator E ₂ . The liquid spouted from the end of the heat transfer tube 7 increases evaporation in the evaporator _E2 . The absorption liquid in the absorber A ₁ and the liquid in the evaporator E ₂ are heat exchanged by a heat exchanger 8a, and the temperature difference between the two liquids is controlled to be minute,
Furthermore, the absorption liquid that has passed through the heat exchanger 8a is transferred to the absorber
The heat is injected downward from the upper part of the heat exchanger tube 7 in A ₁ , and since the area near the top of the heat exchanger tube 7 becomes extremely high in temperature, the heat exchanger 8a is used to preheat the heat exchanger 8a. , absorber
A ₁ and evaporator E ₂ have approximately the same temperature. This action is performed by the chemical heat pumps P ₂ to Pn in the next stage. In the case of Figure 2, absorber A ₁ and evaporator E ₂
The chemical heat pump P ₁ is constructed by the absorber A 2 and the evaporator E ₃ , the P ₂ is constructed by the absorber A ₂ and the evaporator E 3, and the multistage chemical heat pump from P ₃ to Pn is constructed in the same manner.

In addition, the absorption liquid in the absorber A that has been diluted by absorbing the heat medium evaporated from the evaporator E, for example, water, for example,
The LiBr aqueous solution is extracted from absorber A while recovering heat, and is released into the concentrated absorption liquid (high concentration LiBi aqueous solution) in the regenerator, which is stored with solar heat during the intermediate period, and some of the concentrated absorption liquid is transferred to the regenerator. Accordingly, the amount of dilute absorption liquid extracted from the absorber A is returned to the original absorber A according to the amount. On the other hand, the heat medium in the evaporator E evaporates, and the amount of heat medium decreases according to the amount absorbed by the absorber A. However, this is removed from the absorption liquid by the heat pump section consisting of a regenerator and a condenser. The operation of the apparatus is continued by supplying the heat medium (water) obtained by cooling and condensing the water vapor in the condenser from the condenser in accordance with the amount of decrease in the heat medium in the evaporator E.

And, as is clear from Figure 2, the absorber
The heat exchangers 8a to 8n provided in A ₁ to An are all connected in parallel to the heat load 4, and the valves V ₁ to Vn are connected to each section of each heat exchanger 8a to 8n. The valves after the chemical heat pump which has been provided and has reached a constant temperature required by the heat load 4 are closed, and a constant temperature is supplied to the heat load.

That is, if T ₁ is input temperature, T ₂ is output temperature, Q ₁ is heating amount, and Q ₂ is output, then Q ₂ = η ₁・η ₂ …ηn・Q ₁ (η: efficiency per stage,
n: number of stages) T ₂ = T ₁ + _o 〓 ⁱ⁼¹ △Ti (ΔT is temperature rise per stage, n = number of stages).

Next, a calculation example for a two-stage chemical heat pump of this device will be shown.

Operating conditions: a. Low-temperature heat source temperature: 25℃ b. Cooling water temperature: 5℃ c. Absorbent: LiBr d. Refrigerant: water e. High concentration liquid (c ₂ ): 50wt% f. Low concentration liquid ( c ₁ ): 45wt% The solution circulation ratio is a=c ₂ /c ₂ −c ₁ =50/50−45=10 The efficiency η ₁ of the first stage chemical heat pump is calculated from the heat balance per 1 kg of vapor flow. η ₁ =QA ₁ /QE ₁ =io′+(a-1)・i ₂ −a・i ₁ /io′
-io = 608 + (10-1) x 60-10 x 66/68-25 = 0.837 The efficiency η ₁ of the second stage heat pump is: η ₂ = QE ₂ /QE ₂ = io′ + (a-1)・i ₂ −a・i ₁ /io′
-io' = 615 + (10-1) x 65-10 x 73/615-40 = 0.818 where io': Evaporator outflow steam enthalpy (absorber inflow steam enthalpy) io: Evaporator make-up water enthalpy i ₁ : Absorption Enthalpy of drained liquid i ₂ : Enthalpy of absorber replenishing liquid The overall efficiency η is: η = η・η ₂ = 0.685 Hot water at 25°C, which could not be used conventionally, can be used for heating with approximately 70% efficiency with the present invention. , has a large energy saving effect.

〔Effect of the invention〕

As described above, according to the present invention, the following effects can be obtained.

(a) Solar heat collected during the intermediate seasons (spring and autumn) at low temperatures is used as a low-temperature heat source, and this low-temperature heat source is sequentially heated by chemical heat pumps arranged in multiple stages and then supplied to heating loads, etc. By doing so, it is possible to improve the energy saving effect of fossil fuels, etc.

(b) Integrating adjacent absorbers and the next stage evaporator,
In addition, the circulating water in the evaporator, the integrated evaporator, and the integrated evaporator are passed through the heat transfer tubes arranged in common in the absorber, and the circulating water is sprinkled or dripped onto the heat transfer tubes in the evaporator. By doing so, it is possible to reduce the thermal resistance from the absorber to the evaporator, reduce the temperature difference between adjacent absorbers and the next stage evaporator, and improve the efficiency of the multistage chemical heat pump.

(c) Since the heat exchangers of each chemical heat pump P ₁ to Pn are connected in parallel to the heat load via valves, the valves after the chemical heat pump that reaches the constant temperature required by the heat load are closed, and the heat exchanger of each chemical heat pump P1 to Pn is connected in parallel to the heat load. can be supplied to the heat load.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a solar heating system;
FIG. 2 is an explanatory diagram of the multistage chemical heat pump of the present invention, and FIG. 3 is a longitudinal sectional front view showing an integrated structure of an evaporator and an absorber. 1...Solar heat collector, 2...Evaporator, 3...Absorber, 4...Heat load, P1 _~ Pn...Chemical heat pump, _E1 ~En...Evaporator, _A1 ~An... Absorber, 7... Heat exchanger tube, 8a to 8n... Heat exchanger,
V ₁ ~Vn...Valve.

Claims (1)

[Claims] 1 Multiple chemical heat pumps including evaporators and absorbers are combined in series, and except for the uppermost evaporator connected to the solar heat collector, the absorbers constituting each chemical heat pump P1 _to Pn and the next The evaporators of each stage are integrated adjacent to each other, and the absorption liquid in this absorber and the circulating water in the evaporator of the next stage are heat exchanged by a heat exchanger to equalize or minimize the temperature difference between the two. At the same time, a heat transfer tube through which the circulating water in the evaporator flows is commonly disposed in the absorber and the evaporator, and an injection tube for the absorption liquid in the absorber is installed above the heat transfer tube in the absorber. Further, an injection pipe section for circulating water in the heat transfer tube is provided at the upper part of the heat transfer tube disposed in the evaporator, and each of the heat exchangers is connected in parallel to the heat load via a valve. A solar heating device using a multi-stage chemical heat pump, which is characterized by being connected.