Method for heating fresh water for domestic or industrial use

Abstract

A method and apparatus for heating service water and providing heat for the heating of buildings, if required, including a first heat source, a storage tank, and a service water heat exchanger for heating service water, where a simple, robust and efficient system is attained by connecting the first channel of the service water heat exchanger in parallel with the storage tank and by providing a control device, which controls the first circulator pump and the second circulator pump in such a way that in a first operational state the mass flow of the heat transport medium through the first heat source is greater than the mass flow of the heat transport medium through the first channel of the service water heat exchanger, and that in a second operational state the mass flow of the heat transport medium through the first heat source is smaller than the mass flow of the heat transport medium through the first channel of the service water heat exchanger

1 . A method for heating fresh water, and for providing heat for heating of buildings, with a first heat source, a storage tank and a fresh water heat exchanger for heating fresh water, the method comprising:
 conducting a flow of a heat transport medium through the first heat source by a first circulator pump;   conducting a flow of the heat transport medium through a first channel of the fresh water heat exchanger by a second circulator pump;   wherein the first channel of the fresh water heat exchanger is connected in parallel with the storage tank and a control device is provided, which controls the first circulator pump and the second circulator pump in such a way that in a first operational state a mass flow of the heat transport medium through the first heat source is greater than a mass flow of the heat transport medium through the first channel of the fresh water heat exchanger, and that in a second operational state the mass flow of the heat transport medium through the first heat source is smaller than the mass flow of the heat transport medium through the first channel of the fresh water heat exchanger.   
     
     
         2 . The method according to  claim 1 , wherein a partial stream of the heat transport medium is cycled by a second circulator pump via a first mixing valve and a mixing line, if a predefined threshold temperature in the fresh water heat exchanger is exceeded. 
     
     
         3 . The method according to  claim 1 , wherein the fresh water is preheated in a region of the storage tank and is then fed through a second channel of the fresh water heat exchanger. 
     
     
         4 . The method according to  claim 1 , wherein temperature stratification is maintained in the storage tank, and wherein in the first operational state the heat transport medium heated by the first heat source is fed into an upper region of the storage tank, while in the second operational state the heat transport medium exiting from the first channel of the fresh water heat exchanger is fed into a lower region of the storage tank. 
     
     
         5 . The method according to  claim 1 , wherein between the first and second operational states a plurality of other operational states can be selected, which are characterized by a different ratio each between the mass flow of the heat transport medium through the first heat source and the mass flow of the heat transport medium through the first channel of the fresh water heat exchanger. 
     
     
         6 . The method according to  claim 1 , wherein the heat transport medium for fresh water heating is fed directly into a heating system. 
     
     
         7 . The method according to  claim 6 , wherein the heat transport medium for a first heating system is taken from a high-temperature line, which connects a downstream side of the first heat source to the storage tank, while the heat transport medium for a second heating system is taken from a low-temperature line, which connects an upstream side of the first heat source to the storage tank. 
     
     
         8 . The method according to  claim 6 , wherein a back flow of at least one heating system is returned into the storage tank at a point below fittings for the fresh water heating system. 
     
     
         9 . The method according to  claim 6 , wherein the heat transport medium fills and flows through a solar collector when insulation is present to heat the heat transport medium, and wherein the solar collector is drained otherwise, the heat transport medium being collected in a storage tank and kept under increased pressure in the storage tank as well as in the solar collector, and wherein the storage tank is filled partially with the heat transport medium and partially with gas in all operational states. 
     
     
         10 . The method according to  claim 9 , wherein the heat transport medium present in the storage tank has a free surface. 
     
     
         11 . The method according to  claim 1 , wherein a pressure in a system comprising the storage tank, the solar collector and the heating system is maintained at a value of between about 2 bar and about 5 bar. 
     
     
         12 . An apparatus for heating fresh water and for providing heat for heating of buildings, comprising:
 a first heat source,   a storage tank and   a fresh water heat exchanger for heating fresh water,   wherein a downstream side of the first heat source is connected to the storage tank via a high-temperature line and an upstream side of the first heat source is connected to the storage tank via a low-temperature line,   said apparatus further comprising a first circulator pump effecting the flow through the first heat source,   wherein a first channel of the fresh water heat exchanger is fed from the high-temperature line by a second circulator pump connected in series with the first channel of the fresh water heat exchanger and is drained into the low-temperature line, the second circulator pump being controlled independently of the first circulator pump.   
     
     
         13 . An apparatus according to  claim 12 , wherein the first channel of the fresh water heat exchanger is connected to a first mixing valve and a mixing line, through which a partial stream of the heat transport medium can be cycled. 
     
     
         14 . An apparatus according to  claim 12 , wherein a further heat exchanger is provided in the storage tank, whose upstream side is connected to a cold-water fitting and whose downstream side is connected to a second mixing valve, which in turn is connected to a second channel of the fresh water heat exchanger. 
     
     
         15 . An apparatus according to  claim 12 , further comprising a control device which controls the first circulator pump and the second circulator pump in a first operational state in such a way that a mass flow of the heat transport medium through the first heat source is greater than a mass flow of the heat transport medium through the first channel of the fresh water heat exchanger, and which in a second operational state controls the pumps in such a way that the mass flow of the heat transport medium through the first heat source is smaller than the mass flow of the heat transport medium through the first channel of the fresh water heat exchanger. 
     
     
         16 . An apparatus according to  claim 12 , further comprising a heating system directly hydraulically connected to the storage tank. 
     
     
         17 . An apparatus according to  claim 16 , further comprising a first heating system, which is fed from the high-temperature line, and a second heating system, which is fed from the low-temperature line. 
     
     
         18 . An apparatus according to  claim 17 , wherein the first heating system as well as the second heating system are connected to the storage tank on their downstream side. 
     
     
         19 . An apparatus according to  claim 12 , wherein a solar collector is disposed as a second heat source for heating the heat transport medium, the system of the solar collector, the storage tank, the first heat source and the heating system being configured as a closed system, which can be filled under pressure with a single heat transport medium, and wherein the storage tank can be filled with gas in addition to the heat transport medium. 
     
     
         20 . An apparatus according to  claim 19 , wherein the storage tank has a gas space in an upper section, which space is disposed directly above a surface of the heat transport medium. 
     
     
         21 . An apparatus according to  claim 19 , wherein a feeder line to the solar collector is provided, which departs from a lower region of the storage tank and in which a feeder pump is disposed, and wherein a return line is provided, which opens into an upper region of the storage tank above a maximum filling limit for the heat transport medium. 
     
     
         22 . An apparatus according to  claim 12 , wherein means for maintaining temperature stratification are disposed in the storage tank. 
     
     
         23 . An apparatus according to  claim 22 , wherein the means for maintaining temperature stratification is configured as a stratification tube. 
     
     
         24 . An apparatus according to  claim 12 , wherein the first heat source is configured as a condensing gas boiler. 
     
     
         25 . An apparatus according to  claim 12 , wherein the first heat source is configured as a Stirling engine, an internal combustion engine or a fuel cell.