Greenhouse Window U-Factors Under Field Conditions

Publication Type

Journal Article

Date Published

01/1998

LBNL Report Number

LBNL-40448

Abstract

Field measurements of U-factor are reported for two projecting greenhouse windows, each paired with a picture window of comparable insulation level during testing. A well-known calorimetric field test facility was used to make the measurements. The time-varying U-factors obtained are related to measurements of exterior conditions. For one of the greenhouse windows, which was the subject of a published laboratory hotbox test and simulation study, the results are compared with published test and simulation data and found to be in disagreement. Data on interior and exterior film coefficients are presented, and it is shown that the greenhouse window has a significantly lower interior film coefficient than a conventional window under the same interior conditions. This is advanced as a possible explanation of the disagreement.

Journal

ASHRAE Transactions

Volume

104, Part 1

Year of Publication

1997

Call Number

LBNL-40448