Laboratory energy recovery selection factors

Brown (1990) recommends that a

Heat recovery coil should be incorporated for geographic regions with high preheating/humidification requirements.

a.Locate coil upstream of preheating coil in cold climates.

b.Coil can be located downstream of fan in non-severe climates to maximize benefits of pre-cooling where applicable.

The American Conference of Governmental Industrial Hygienists Industrial Ventilation: A Manual of Recommended Practice (1995) discusses issues in selecting heat exchangers.

Several factors are important in the selection of the appropriate heat exchanger. A partial list is as follows:

• The nature of the exhaust stream. A corrosive or dust laden stream may need to be pre-cleaned.
• The need to isolate the contaminated exhaust stream from the clean replacement air stream.
• The temperature of the exhaust stream. Unless the box air stream is well above the desired delivery temperature of the replacement air stream and the exhaust air stream is at elevated temperatures whenever heat is demanded by the replacement air stream, additional heating capacity will be required.
• Space Requirements. Space requirements for some heat exchangers can be very extensive, especially when the additional duct runs are considered.
• The nature of the air stream. Many exhaust air streams are corrosive or dirty and special construction materials may be required.
• The need for a by-pass. During failure mode or summer conditions, a by-pass will be required.