Ductless Heat Pumps Sizing Example. Gary Nordeen Bill Kingrey, P.E. 11/5/08 AFE Webinar. www.nwBuildings.org/dhp.aspx info@nwBuildings.org. Introduction. This presentation is intended to show how a ductless heat pump is sized for a particular space.
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Gary NordeenBill Kingrey, P.E.11/5/08 AFE Webinar
This presentation is intended to show how a ductless heat pump is sized for a particular space.
The example is a maternity room inside a health facility, that needs supplemental cooling.
Calculate the heat loss through walls, glass, ceiling/roof, floor and any other building components in the zone to be served, using ASHRAE procedures (chapter 26, Fundamentals)
Assume we are going to provide cooling to a maternity room that is currently heated and ventilated by a central system with heating and ventilation air. We surveyed the room and found the following existing conditions.
2x32 + 65 + 2 x 275 = 679 watts
679w X 3.412 BTU / watt = 2317 BTUH Sensible
40CFM x 1.08 BTUH / CFM x ºF x (92ºF – 75ºF) =734 BTUH
4,800 BTUH (envelope) + 2,317BTUH + 734 BTUH = 7,850 BTUH Sensible
To calculate latent loads, use a Psychometric Chart or software that will determine enthalpy and density of water/air mixtures
= 1,440 BTU/hr
= 210 + 1440 =1,650 BTU/hr
(about 1.5 pints of water per hour)
Northwest Building Efficiency Center