Heat Recovery for Air Conditioning

[Student Eng]

Hello,

Ive been given an assignment in college on Heat Recovery systems. Ive done most of the assignment but to complete it could someone help me with the last couple of questions.

What problems could arise if the systems are not set up properly?

What factors can be affected by a failure to provide adequate maintenance?

The systems Ive chosen are Heat Pipes,
Run around systems and Heat Wheels.

Any help would be much appreciated

Regards

Stu Eng

[NoNickName]

This is new... what is a run around system? By heat wheel you mean rotative recovery?

[US Iceman]

Unless the student is describing something else, a run around system is a pumped glycol system between two heat exchangers.

Another item to look at for heat recovery is using a thermosiphon system with two heat exchangers. Works very nice.

[Brian_UK]

What problems could arise if the systems are not set up properly?

What factors can be affected by a failure to provide adequate maintenance?

If it is not set up properly then obviously performance will suffer. Also mechanical failure could be hastened as the components that should be cooled by the process may not be and will operate outside their design parameters.

Inadequate maintenance can cause all sorts of problems depending on the equipment requirements. Think of it like a car, if you drive it for long enough without checking or changing the oil then the engine will suffer. Eventually it will fail. Now you can't blame the engine for giving up can you?

[Student Eng]

Thanks for all your help

Cheers

Student Engineer

[vijay_study]

Hi Student eng,

Heat recovery systems are used for 100% fresh air air conditioning systems.

It basically utilises the lower temperature or exhaust air compared to incoming fresh air.

There are two types of heat recovery wheels

1. Heat pipes : These can provide sensible heat recovery however latent heat recovery capacity of heat pipes is limited.

2. Enthalpy wheels: Enthalpy wheels provide maximum heat recovery efficiency of 75% both sensible and latent.

Suppose the heat recovery does not function then the capacity of cooling coil will be much less to cool the entire fresh air. This will lead to an increase in inside room temperature and relative humidity.

There are a lot of things that can go haywire in case proper maintenance is not provided.

Utimately the customer should get the design temperature and humidity. Therefore, maintenance should be proper.

Regards