METHOD FOR UTILIZING HEAT OF COMPRESSION

Abstract

Described is a method for utilizing the heat of compression accumulating during a compression process for air-conditioning and/or heating buildings and/or for heating service water. According to the invention, the heat of compression accumulating during the compression process is at least temporarily transferred to at least one consumer that serves for air-conditioning and/or heating a building and/or for heating service water by means of at least one refrigerant circuit.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application Serial No. DE 102009013755.6 filed Mar. 17, 2009.

BACKGROUND OF THE INVENTION

The invention pertains to a method for utilizing the heat of compression accumulating during a compression process.

Energy is required for heating and air-conditioning buildings, as well as for heating service water, and therefore needs to be supplied and/or generated directly on-site. In order to lower the energy requirement, excess energy is already utilized for the aforementioned purposes in a number of applications. In many applications, however, energy is needed for heating or cooling buildings while energy simultaneously is or must be wastefully dissipated because it could not be “recycled” so far.

Natural gas and hydrogen fueling stations feature a number of buildings that need to be at least temporarily heated or cooled. If such fueling stations also feature a car wash, the service water required for this car wash also needs to be heated. The natural gas or hydrogen sold at such a fueling station needs to be compressed before a vehicle is refueled. Until now, the heat of compression released during the compression of these mediums was wastefully dissipated by means of a suitable cooling system—in which water or ambient air is used as cooling medium. The compression of the aforementioned mediums to pressures up to 1000 bar requires an expenditure of energy between 15 and 300 kW, wherein the same amount of energy is generated in the form of heat and had to be transferred to the surroundings so far with the aid of corresponding heat exchangers.

SUMMARY OF THE INVENTION

The present invention is based on the objective of disclosing a method of the initially cited type for utilizing the heat of compression accumulating during a compression process, wherein said method eliminates the above-described disadvantages and makes it possible, in particular, to utilize the heat of compression accumulating during a compression process for air-conditioning buildings, for heating buildings and/or for heating service water.

In order to attain this objective, the invention proposes a method of the initially cited type for utilizing the heat of compression accumulating during a compression process, wherein said method is characterized in that the heat of compression accumulating during the compression process is at least temporarily transferred to at least one consumer that serves for air-conditioning and/or heating a building and/or for heating service water by means of at least one refrigerant circuit.

Other advantageous variations of the inventive method for utilizing the heat of compression accumulating during a compression process form the objects of the dependent claims and are characterized in that

• • the inventive method is implemented in a gas fueling system, in which a one-stage or multi-stage compression of a medium, preferably natural gas or hydrogen, is realized and
  • the medium circulating in the refrigerant circuit consists of water and/or glycol.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive method for utilizing the heat of compression accumulating during the compression process for air-conditioning buildings, for heating buildings and/or for heating service water, as well as other variations thereof, are described in greater detail below with reference to the exemplary embodiment illustrated in the FIGURE. However, this FIGURE merely shows a schematic representation of the inventive method.

DETAILED DESCRIPTION OF THE INVENTION

A gaseous medium to be compressed is fed to a pre-compressor V1 via a line 1 and compressed to a desired intermediate pressure therein. In the case of a natural gas or hydrogen fueling station, this intermediate pressure lies in the range between 12 and 27 bar. The pre-compressed medium can either be intermediately stored in a storage device that is not illustrated in the FIGURE and/or directly fed to the main compressor V2 via a line 1′. The medium is compressed to the desired ultimate pressure in this main compressor. In the compression of natural gas or hydrogen, this ultimate pressure usually lies between 250 and 1000 bar. The compressed medium is subsequently fed to a vehicle to be refueled—if applicable after a corresponding intermediate storage—via a line 1″. The compression of the gaseous medium to be compressed may also be realized in only one compression stage or in more than two compression stages.

The pre-compressor V1 and the main compressor V2 are respectively provided with a heat exchanger E1 and E2—that is illustrated in the form of the broken lines connecting the respective compressor and the assigned heat exchanger. The heat exchangers E1/E2 serve for dissipating the heat of compression created during the compression in the two compression stages V1/V2. The temperature usually increases by 50 to 150 K per compression stage.

The two heat exchangers E1 and E2 are connected by a refrigerant circuit 2-5. A refrigerant that is suitable for the respective application circulates in this refrigerant circuit, wherein the refrigerant may consist, in principle, of a one-component or multi-component refrigerant. In many applications, it is sufficient and practical to use water as the refrigerant.

A consumer E3 that receives a medium via a line 6 and discharges a medium heated or cooled therein via a line 6′ is illustrated in the FIGURE in a purely exemplary fashion. The consumer E3 may consist, for example, of a heater, an air-conditioner or a device for heating service water that is preferably realized in the form of an adsorption system, an absorption system or a DEC-system (Desiccant and Evaporative Cooling). In this case, the medium fed to the consumer E3 via the line 6 would respectively consist of air or service water. Several consumers will exist in many applications, but these consumers do not necessarily have to always operate simultaneously.

It is advantageous to provide an additional heat exchanger E4 that makes it possible to realize a degradation or dissipation of the energy released during the compression—for example in the form of a heat transfer to cooling water or ambient air—when an “energy consumption” by the or at least one of several consumers E3 is impossible or undesirable.

The inventive method for utilizing the heat of compression accumulating during a compression process now makes it possible to cost-efficiently provide the energy or the majority of the energy required for heating or air-conditioning buildings.

The inventive method for utilizing the heat of compression accumulating during a compression process can also be subsequently implemented in existing processes or systems, in which a compression process is realized.

Claims

1. A method for utilizing the heat of compression accumulating during a compression process selected from the group consisting of air-conditioning, heating buildings, and heating service water, characterized in that the heat of compression accumulating during the compression process is at least temporarily transferred to at least one consumer selected from the group consisting of air-conditioning, heating a building, and heating service water by means of at least one refrigerant circuit.

2. The method according to claim 1, wherein the method is implemented in a gas fueling system, in which a compression of a medium is realized.

3. The method according to claim 1, wherein said compression of a medium is selected from the group consisting of one-stage and multi-stage.

4. The method as claimed in claim 2, wherein said medium is selected from the group consisting of natural gas and hydrogen.

5. The method according to claim 1, characterized in that the medium circulating in the refrigerant circuit is selected from the group consisting of water and glycol.