Before field studies of the advanced HVAC began, the system was evaluated onsite at Lawrence Berkeley National Laboratory using a simulated classroom setting. Lab evaluation occurred during the summer and fall of 2004. A single RC unit was installed at LBNL for testing. The classroom was outfitted with the advanced HVAC system as well as a standard 10 SEER HVAC system for comparison. Sensors were installed to monitor indoor air quality, temperature and energy use. 30 light bulbs were used to simulate the thermal presence of students during the day and CO₂ was released at a controlled rate to simulate the occupant's respiration.

While final analysis of the data collected is underway, preliminary results look favorable. The advance HVAC system was able to be directly bolted onto the RC without major modification and used about 56% of the energy of the control 10 SEER HVAC system. In addition, the operational noise produced by the advanced HVAC system was lower than the goal of 45 dB(A). The worst-case integrated (A-weighted) noise level recorded for the advanced HVAC was 43 dB(A) when the heat pump was operating on high, while integrated (A-weighted) noise levels were below 32 dB(A) when only the fan was operated (see octave band sound pressure level (SPL) graphs below).

In addition to the meeting and exceeding the energy savings and noise level reduction goals, the ventilation and thermal conditioning units were successfully decoupled allowing for ventilation at anytime regardless of the indoor temperature. This is important because it allows for ventilation independently of heating or cooling the classroom. During the lab studies, it was also established that the advanced HVAC system could provide adequate thermal comfort while meeting all of the mentioned goals.

Field Study