Underheated VAV with No reheat
I am currently investigating the potential savings of using a small scale VAV system for single family homes. The intent is to compare two models:
- The baseline model uses central heating and cooling and supplies air at constant volume. The HVAC system is controlled by a single thermostat.
- The proposed model uses the same heating and cooling systems, but supplies varying amounts of air to the spaces based on individual thermostats placed in each room. For this reason, the model is multizonal, even though it's a single family home. No terminal units are used for reheating before air enters the individual spaces.
I am using eQuest to compare the two scenarios but am already having trouble with unmet load hours for the baseline model. My current set up on the Air Side is a single VAV system serving multiple zones. The VAV system uses a chilled water loop for cooling and a boiler for heating. Zone heat source is not installed because no terminal reheating is provided. The baseline model is underheated for around 5000 hours. I am letting eQuest autosize the heating capacity, but it sizes to 0. Looking at other threads, I've tried setting the hot deck temperature to 65 but the heating capacity is still 0. I’ve also increased the throttling range to 6 degrees but this only reduces a small amount of the underheated hours.
Any help would be greatly appreciated!
