What are the types of heat recovery devices?

In HVAC Industry following are the most comply used heat recover devices:

- Use of desiccant Wheel

- Heat Pipe

- Run Around Pipe

- Twin Tower Energy Recovery System

1.   Recuperators: This name is given to different types of heat exchanger that the exhaust gases are passed through, consisting of metal tubes that carry the inlet gas and thus preheating the gas before entering the process. The heat wheel is an example which operates on the same principle as a solar air conditioning unit.

2.   Regenerators: This is an industrial unit that reuses the same stream after processing. In this type of heat recovery, the heat is regenerated and reused in the process.

3.   Heat pipe exchanger: Heat pipes are one of the best thermal conductors. They have the ability to transfer heat hundred times more than copper. Heat pipes are mainly known in renewable energy technology as being used in evacuated tube collectors. The heat pipe is mainly used in space, process or air heating, in waste heat from a process is being transferred to the surrounding due to its transfer mechanism.

4.   Thermal Wheel or rotary heat exchanger: consists of a circular honeycomb matrix of heat absorbing material, which is slowly rotated within the supply and exhaust air streams of an air handling system.

5.   Economizer: In case of process boilers, waste heat in the exhaust gas is passed along a recuperator that carries the inlet fluid for the boiler and thus decreases thermal energy intake of the inlet fluid.

6.   Heat pumps: Using an organic fluid that boils at a low temperature means that energy could be regenerated from waste fluids.

7.   Run around coil: comprises two or more multi-row finned tube coils connected to each other by a pumped pipework circuit.

as per ASHRAE system and equipment chapter

- fixed plate

- membrane plate

- energy wheel

- heat wheel

- heat pipe

- runaround coil loop

- thermosiphon

- twin towers

heat recovery wheel used to improve the efficiency of the system  by absorbing the heat from from atmospheric air or fresh air and mixing it with return air so that the fresh air can be pre  cooled before  sending it to condition space.

Heat Recovery wheel

it Use in AHU  where 100% Freash Air Requied