Thermal Performance Evaluation of a Small Duct High Velocity System Using NISTs Net-Zero Energy Residential Test Facility
Khiem Nguyen, Hyojin Kim, Lisa C. Ng, William V. Payne
This study aims to evaluate the performance of a Small Duct High Velocity (SDHV) heat pump by comparing it with the Conventionally-Ducted Heat Pump (CDHP) using one-year of detailed data from the two-story Net-Zero Energy Residential Test Facility (NZERTF) on the campus of the National Institute of Standards and Technology (NIST). The NZERTF is a single-family home but is also a laboratory with simulated occupancy and scheduled internal loads. During the analysis period, the SDHV and the conventionally-ducted systems were alternately operated every other week in order to allow a comparison between the two under similar weather conditions. The preliminary analysis indicated that the SDHV system might not always provide superior thermal comfort compared with the CDHP. Potential reasons are lower supply airflow rates from the SDHV during the heating season in this low-load house; and extremely tight throttling range of the CDHP. Additional analyses are needed to confirm the findings.