RU2587737C1 - Method of increasing thermal potential of heat source - Google Patents

Abstract

FIELD: energy.

SUBSTANCE: invention is aimed at energy saving by rational use of renewable sources of heat and natural temperature drop in environment. Disclosed is a method of producing heat energy in a closed adsorptive cycle enhancement of temperature potential, consisting of consecutive steps of adsorption of cooling agent on adsorber, removal of cooling agent with adsorbent (regeneration), evaporation and condensation of cooling agent, adsorbent regeneration is performed by heating from renewable source of low-potential heat, and condenser is cooled to low temperature by using only natural temperature drop in environment.

EFFECT: invention increases temperature potential of heat source only due to use of natural temperature difference in environment.

3 cl, 2 dwg

Description

The invention relates to the field of energy and is aimed at energy saving through the rational use of renewable heat sources and the natural temperature difference in the environment.

Currently, the basis of energy is non-renewable energy sources. In connection with the exhaustion of fossil fuel resources, the problem of the rational use of alternative energy sources, industrial heat, waste water and other waste heat is an urgent problem. The main problem of using such sources is their relatively low temperature potential, which is insufficient for the heat released into the environment to be used with benefit, for example, for heating or heating water. This problem is solved by increasing the temperature potential of the used heat source in thermotransformers. A typical example of such a thermotransformer is a split air conditioning system (Ananyev V.A. et al. Ventilation and air conditioning systems. Theory and practice. 2001, 416 p.), Operating in heating (heating) mode. As a heat source, this system uses ambient heat with a low temperature potential, generates heat with a temperature potential sufficient to heat the air in the room, and uses electric energy to drive the system.

An analogue of a split air conditioning system operating in heating mode is a utility model (RF 77030, F25B 30/02, 10/10/2008), designed for heating rooms using wastewater heat. A distinctive feature of this utility model is the use of a compressor.

In the patents (RF 2256126, F24D 3/02, 07/10/2005) and (US 8418466 F01K 7/32, 04/16/2013) a method for increasing the temperature potential of a heat source through the use of a vortex tube is proposed. This method also requires the use of mechanical compressor energy.

Another example of a thermal transformer for converting low-grade heat to heat with an increased temperature potential is absorption and adsorption heat pumps. This is achieved by conducting a closed cycle of adsorption-desorption of the refrigerant, accompanied by absorption of heat in the evaporator, which is maintained at ambient temperature, and its release in the condenser and adsorber at a higher temperature, sufficient for the needs of the consumer. The activation of the cycle is carried out by regeneration of the absorbent (adsorbent) at elevated temperature by using another source of heat, usually 80-350 ° C (link).

So, in the patent (RF 2358209, F24J 3/08, 06/10/2009) a method for using the heat of geothermal water for heating purposes using a heat pump is proposed. The method is characterized in that it uses a heat source with a temperature of T> 80 ° C, and the consumer receives water with a temperature of 55-65 ° C.

The patent (CA 2674245, C01B 3/06, 02/01/2010) proposes a method for using a chemical heat pump to increase the temperature potential of a heat source. The method is characterized in that low-grade heat is absorbed during decomposition of the ammonium complex of manganese, heat with an increased temperature potential is released during the formation of ammonia complexes of manganese sulfate and nickel chloride, and the cycle is activated by decomposition of the ammonia complex of nickel chloride. The latter process occurs at a higher temperature compared to the temperature at which useful heat is given to the consumer.

The prototype of this invention is an adsorption heat pump (US 7497089, B01J 29/06, 03.03.2009) containing an adsorbate (refrigerant), an evaporator, a condenser and an adsorption-desorption part with an adsorbent. In this prototype, water vapor is used as an adsorbate (chaladgent), and SAPO-34 aluminophosphate as an adsorbent. The principle of operation of the prototype under consideration is that the adsorbent, which is at a temperature of 40-45 ° C, absorbs water vapor and the heat is released. Evaporation of water occurs in the evaporator at a temperature of 5-10 ° C. Thus, the transformation of heat with a low temperature potential into heat with a higher temperature potential occurs. To regenerate the adsorbent in the prototype under consideration, it is heated to a high temperature, most preferably to 60-95 ° C.

The above examples of methods for increasing the temperature potential have a common feature that they use an external source of energy, either electrical, mechanical or thermal, with a potential exceeding the temperature potential of the received useful heat. Thus, the above methods really lead to an increase in the temperature potential of "waste" heat, to an increase in its quality. However, all of the above methods use energy sources with an even higher quality than can be obtained and transmitted to the consumer.

The invention solves the problem of increasing the temperature potential of a heat source by using the natural temperature difference in the environment and without using electrical, mechanical energy and / or a heat source with a higher temperature potential.

A method for increasing the temperature potential of a heat source in a closed adsorption cycle of increasing the temperature potential, consisting of successive stages of refrigerant adsorption on an adsorbent, removal of refrigerant from an adsorbent — regeneration, evaporation and condensation of a refrigerant in which the adsorbent is regenerated by heating it from a renewable source of low-grade heat, is proposed. while the condenser is cooled to a low temperature using an exclusively natural temperature difference in the environment In this case, activated carbon, natural or synthetic zeolite, zeolite-like material or composite adsorbent are used as adsorbent, alcohols or ammonia are used as a refrigerant adsorbent.

As a renewable heat source, geothermal water, non-freezing water, industrial and domestic wastewater and other heat sources with a temperature of T _East = 0-35 ° C, mainly 4-20 ° C are used.

The ambient temperature is (-50) - (- 5) ° С, mainly (-25) - (- 15) ° С.

The method allows to achieve an increase in the temperature potential of a source of low potential heat by 5-20 ° C, and with cascade implementation - by 40 ° C and above.

To solve the problem, a closed adsorption cycle of increasing the temperature potential is proposed, in which the regeneration stage is carried out due to the natural temperature difference in the environment. The adsorption cycle (Fig. 1) consists of two isosteres (1-2 and 3-4) and two isotherms (2-3 and 4-1). The temperature parameters of the cycle are set by three temperatures: ambient T _okr , heat source T _East and target temperature T _c , where T _okr <T _East <T _c . The adsorption thermal converter (Fig. 2) consists of an adsorber (1) containing an adsorbent (2), and a tank (5) with refrigerant (4), which acts as an evaporator and condenser. The adsorber and container are sealed and connected using a vacuum valve (3). Initially, the adsorbent is in a regenerated state (the isostere w1 corresponds to a low adsorbate content) at the source temperature T _East (point 1 of Fig. 1), the container with the refrigerant is maintained at the same temperature. The valve connecting the container with the adsorbent and the container with the refrigerant is opened. The refrigerant evaporates in the tank and its vapor is adsorbed on the adsorbent. This causes heating of the adsorbent, and heat release occurs when the target temperature T _c greater than T _u source> T _ist temperature (point 2 of FIG. 1). The resulting useful heat is used for heating needs. After reaching the adsorbate content w2 (point 3 of Fig. 1), the valve is closed. To regenerate the adsorbent, it is maintained at the temperature of the heat source T _East (point 4 of Fig. 1). The refrigerant tank is cooled to ambient temperature T _okr and the vapor pressure of the refrigerant in the tank becomes less than the equilibrium vapor pressure above the adsorbent. The tap between the tank with the refrigerant and the adsorbent is opened, which leads to regeneration of the adsorbent. At the end of the regeneration process, the valve is closed, and the tank with the refrigerant is heated to the temperature of the heat source. Thus, the adsorbent returns to its original state (point 1 of Fig. 1) and the adsorption cycle closes.

The invention is illustrated by the following examples and illustrations.

In FIG. 1 shows the adsorption cycle of increasing the temperature potential. In FIG. 2 shows a device for an adsorption heat converter.

Example 1

A composite methanol sorbent (US Pat. RF 2294796) in an amount of 1 kg, saturated with methanol vapor, is placed in a container and heated to a temperature of 20 ° C, a container with liquid methanol is cooled to a temperature of -20 ° C. After reaching the indicated temperatures, the containers with adsorbent and methanol are connected, opening the shut-off valve, the adsorbent is regenerated. At the end of the regeneration, the valve is closed, the methanol tank is heated to a temperature of 20 ° C. After the containers reach a constant temperature, the tap is opened and adsorption begins. The adsorbent heating is 35 ° C, the heat release is 407 kJ. The regeneration-sorption process is cyclically and reproducibly repeated, the heating is 35 ± 2 ° C, the heat release is 400 ± 20 kJ.

Example 2

Analogously to example 1, a container with liquid methanol is cooled to a temperature of -25 ° C. The heating is 38 ± 2 ° C, the heat is 420 ± 20 kJ.

Example 3

Analogously to example 1. The methanol tank in the regeneration stage is cooled to -50 ° C, the adsorbent is maintained at a temperature of 4 ° C. In the adsorption step, the methanol tank is heated to a temperature of 4 ° C. Warming up is 25 ° C, heat dissipation is 350 ± 20 kJ.

Example 4

Analogously to example 1, mesoporous silica gel containing a mixture of calcium chloride and calcium bromide in the pores is used as an adsorbent, and the container with liquid methanol is cooled to a temperature of -15 ° C. The heating is 33 ± 2 ° C, the heat release is 300 ± 20 kJ.

Example 5

Analogously to example 1. Activated carbon is used as an adsorbent. Warming up is 24 ° C, heat dissipation is 150 ± 20 kJ.

Example 6

Analogously to example 2. Zeolite is used as an adsorbent. The heating is 27 ± 2 ° C, the heat release is 210 ± 30 kJ.

Example 7

Analogously to example 6. Synthetic zeolite-like material is used as an adsorbent. Warming up is 28 ± 2 ° C, heat dissipation is 230 ± 20 kJ.

Example 8

Analogously to example 5. Ammonia was used as a refrigerant. The heating was 30 ± 2 ° C, the heat release was 260 ± 30 kJ.

Example 9

Analogously to example 1. The heat generated in the cycles is used to heat a copy of the device similar to example 1 to the initial temperature of 35 ° C after regeneration under the conditions of example 1. During adsorption, the adsorbent is heated in the second device at 60 ° C, the heat release is 300 kJ.

The above examples show that using a closed adsorption cycle to increase the temperature potential and using the natural temperature difference in the environment, the problem of increasing the temperature potential of a heat source without using electric, or mechanical energy, or thermal energy with a higher temperature potential than the target temperature is solved.

The technical result of the invention is to obtain useful heat with a temperature potential higher than the temperature potential of the waste heat used to drive the device.

The method allows to achieve an increase in the temperature potential of a source of low potential heat by 5-20 ° C, and with cascade implementation - by 40 ° C and above.

Claims (3)

1. A method of increasing the temperature potential of a heat source in a closed adsorption cycle of increasing the temperature potential, consisting of successive stages of refrigerant adsorption on an adsorbent, removal of refrigerant from an adsorbent — regeneration, evaporation and condensation of a refrigerant, characterized in that the adsorbent is regenerated by heating it from a renewable source low-grade heat, while the condenser is cooled to a low temperature using an exclusively natural temperature difference of environment, while activated carbon, natural or synthetic zeolite, zeolite-like material or composite adsorbent are used as adsorbent, alcohols or ammonia are used as a refrigerant adsorbent. 2. The method according to p. 1, characterized in that as a renewable source of heat use geothermal water, non-freezing water, industrial and domestic wastewater and other heat sources with a temperature of T _East = 0-35 ° C, mainly 4-20 ° C . 3. The method according to p. 1, characterized in that the ambient temperature is (-50) - (- 5) ° C, mainly (-25) - (- 15) ° C.

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