Submission
Field Measurement On Rooftop Condensing Unit Before And After Reconstruction
DOI: 10.18462/iir.compr.2021.0366
Session: Field measurements
Accept state: Submission accepted
Authors
| Name | Organization | |
|---|---|---|
| Peter Tomlein, Doc. Ing.PhD. | SZ CHKT |
Abstract
Packaged cooling only rooftops (hereinafter referred to as rooftop) equipped with AC fan motors on condensing unit can be retrofitted to fans with EC motors. Economy of fan retrofits depends on operation time, which is short in cooling mode. Reconstruction of rooftops from cooling-only to heating-also mode enables longer operation time and better retrofit and reconstruction economy. Methodology for heat balance calculation in cooling and heating mode can differ. Monthly method according to STN EN ISO 13790 and hourly method according to EN ISO 52016-1 were used to calculate thermal balances of the building. Importance of the new hourly method is demonstrated in comparison with the commonly used monthly method. Efficiency and operation time of the heat pump depended on on/off compressors, which operation range had to be limited. Field measurement showed higher efficiency after fans retrofit. Efficiency of reconstruction from cooling-only to heating-also mode depends on the extent of reconstruction. Field measurement showed a need for precautions against possibly risky compressor operation.
Keywords
Field measurement, fans, electric motor, on/off compressor, rooftop cooling only