Which device is used to reduce energy consumption in HVAC by reclaiming energy?

• A. Economizer
• B. Thermostat
• C. Venturi meter
• D. Solenoid valve

Answer: (A)

Using outdoor air to meet part of the cooling load when conditions are favorable is a practical way to cut HVAC energy use. This is what an economizer does: it senses outdoor conditions and, when cooler outside air can effectively cool the space, it opens dampers to bring in that air instead of running the compressor and mechanical cooling. By offsetting the need for refrigerant-based cooling, energy consumption drops. A thermostat simply manages the indoor temperature without reclaiming energy; a venturi meter measures flow, not energy; a solenoid valve controls fluid flow but doesn’t provide energy recovery. So, the device that reduces energy use by reclaiming energy in HVAC is the economizer.