Method and device for recovering energy

Abstract

Existing energy recovery systems are used in the fields of air conditioning and ventilation for recovering energy from the outgoing air or external air. Subsequent to an energy recovery system (10), additional thermal energy is extracted from a used air volume flow AB, which is coming from an air-conditioned room, by another system, which consists of a heat pump (3), a heat exchanger (1), another heat exchanger (2), an accumulator circuit (9), an energy accumulator (9.1), and of a mixing valve (6). The associated supply air volume flow ZU is, when heating, additionally heated by the heat pump (3) by means of thermal energy from the used air volume flow AB. This results in increasing the energy yield from the used air volume flow AB. The temperature of the supply air is regulated. When cooling, the supply air volume flow ZU is cooled to the desired supply air temperature.

Description

FIELD OF THE INVENTION [0001] The invention relates to a method for recovering energy from an air-conditioning and / or ventilation system. BACKGROUND OF THE INVENTION [0002] Heat recovery systems, systems with recuperative and regenerative heat exchangers, and also systems with an intermediate medium or heat pumps are used in air-conditioning and ventilation technology for recovering energy from the used or outgoing air. [0003] In the literature, heat recovery systems are described in many forms. Such systems are known in ventilation technology and used frequently. According to the literature, so-called return-heat indices of up to 0.8 can be achieved. [0004] In the publication “Recknagel, Sprenger, Schramek; Handbook for Heating+Air-conditioning Technology Jan. 02, 2001 edition, Oldenbourg Industrieverlag Munich” on pages 1367ff., various techniques for recovering heat are described. Among other systems, this publication also mentions a system with a heat pump. [0005] Additional clu...

AI Technical Summary

Benefits of technology

[0028] Among other things, the advantages that can be achieved with the invention consist of the advantageous effects described below:

[0029] 1. An extremely large heat recovery is achieved. The transfer power WRG achieved with the heat recovery system is increased by the heat pump system configured in the described combination. It is possible to remove more energy from the used air volume flow than is necessary for the heating of the supply air volume flow. The excess energy can optionally be used also for heating service water, e.g., also for heating after the adiabatic humidification of the supply air volume flow.

[0030] In comparison with other heat recovery systems, due to the controllable heat recovery system, the value of the return heat index can exceed 1, while in other, known heat recovery systems, a maximum economical return heat index of 0.8 is achieved. EXAMPLE

[0032] The used air volume flow is cooled with an interconnected circulating system, with a return heat index of 0.47, in combination with the heat pump system from 24° C. at 50% relative humidity to 6.8°:

[0036] The external air enters at 10° C. at 70% relative humidity. The supply air volume flow is then converted by the treatment into the state of 31° C. at 19% relative humidity:

[0040] From this follows for the value of the return heat index: ϕ=24⁢°C-6.8⁢°C24⁢°C-10⁢°C=1.23

Problems solved by technology

A sliding control over the entire range of the various outside temperatures is not possible with any of the systems without reducing the so-called output number.

With prior systems, switching from cooling mode to the heating mode and vice versa cannot be controlled effectively, if at all, or only with worse efficiency by means of air mixing.

The air-conditioning system has a complicated shape, can only be poorly controlled, and requires, for the cooling case, an additional cooling unit, which must be connected into the supply air by means of another heat exchanger.

Consequently, for a conventional ventilation system, the described state of the art produces a not insignificant additional expense in terms of devices for the heating or cooling of the supply air volume flow to be generated.

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