The HEAT RECOVERY SYSTEM is a vessel that generates and stores heated water and in which the water is heated through a heating element which preferably is the condenser of a cooling aggregate. The water thereby flows into the bottom of the vessel, which is insulated against loss of heat, and is withdrawn from the top.

Such commonly known installations tend to feature a heating element which is located openly

in the inside of the vessel, creating a rising stream of heated water through the local water heat- up. The drawback is that due to the convection current the water in the vessel reaches an even, average temperature.

A further drawback is that a significant amount of time lapses after starting the installation before water can actually be withdrawn that has reached a sufficiently high temperature. For any operation with a heater that works only temporarily the water temperature will immediately sink when withdrawing water and supplying cold water if the heater no longer operates, which is the case for a cooling unit. A further disadvantage is that the entire surface of the vessel takes on the heated water, thus creating an unnecessary loss of heat.

Of particular importance is that the heater (condenser) has no more available cold water after a short operation time of the unit only, and that therefore an optimum use of heat is no longer guaranteed.

In designing the HEAT RECOVERY SYSTEM is was our task to find a vessel to generate and store heated water which was especially suitable for the utilisation of waste heat of a condenser of a refrigeration unit and which enables, immediately following the start of operation, a withdrawal of water with the highest possible temperature and which, on the other hand, constantly supplies the condenser with cold water until complete replenishment of the vessel with hot water.

This installation was further to be of simple structure, economic production and was to enable an uninterruptable continuous operation over longer periods of time.

The HEAT RECOVERY creates water layers inside the vessel.

When operating th installation, a layer of hot water builds up at the top, beneath which a thin interim layer of m dium water temperature and below a layer of cold water. The temperature difference of 35 can be achieved without any difficulty, i.e.: the cold water can reach + 10°C at the bottom while the heated water can reach +45°C/60deg C at the top.

These water layers are created through a riser tube whose flow resistance is dimensioned as such that the heating element (condenser) has a sufficiently large flow rate to maintain its desired operating temperature while on the other hand allowing the flow to be so slow that there is no turbulence to the top of the water outlet and that hot water can settle evenly throughout the vessel without any turbulence.

The heating element (condenser) comprises a finned helical tube through which hot gas or any other suitable heat carrying medium flows.

The flow crosses the helix from top to bottom so that at the ratio of the water flowing through the riser rube there is a counterflow heat exchange with the highest possible end temperatures.