Design and Construction of a New Psychrometric Chamber

Abstract

The complete design and construction of a psychrometric chamber resulted in the following conclusions:* Chamber dimensions of 25' x 40' x 20* Temperature rage of -40 to130�F (-40 to 54 �C) and 10 to 90% relative humidity * Cooling capacity of 15 tons (52.7 kW) and airflow rate of approximately 8000cfm.* The chamber consists of sheet metal panels filled with a polyurethane foam core; the estimated thermal conductivity of a panel is 0.026 - 0.033 W/m-K (0.015 - 0.019 Btu/hr-ft-F). * Simulation suggests chamber operation down to about -25�F (-32�C) before formation of condensate on the exterior walls* The chamber was specifically designed to incorporate industry standards for testing using the indoor and outdoor air enthalpy methods* Low and high temperature hydronic cooling systems were designed and installed for chamber operation* Based on preliminary simulations using customized subroutines in HVACSIM+, the soaking time of the chamber for 25 to 0�C (77 to 32�F) is expected to be about 2.5 hours. The soaking time down to -40�F is approximately 4 hours. * The chamber structure and supporting systems have been constructed and await operation.