Energy Recovery and Conservation Strategies

Introduction

Energy conservation and energy recovery strategies can be used to reduce reliance and overall use (cost) of a building's HVAC system. These strategies can involve mechanical systems, heat transfer methods, building automation systems, and building commissioning.

Energy Use

The amount of energy used by a typical building's HVAC system is about 40-60% of its overall energy consumption. This is heavily dependent on type, climate, design, building use, and efficiency of the system.

• Some type of mechanical system is typically always involved in buildings regardless of size, so using energy-efficient mechanical systems is a good strategy for energy conservation.
• The National Appliance Energy Conservation Act of 1987 set minimum energy efficiency standards that all small and large heating and cooling equipment needed to follow. Generally speaking, heating and cooling equipment keep getting more efficient with technology upgrades, however, they also tend to have more parts like circuit boards that may fail.

Recovery Strategies

Dual-Condenser Cooling

Dual condenser cooling is a system that uses two refrigeration circuits (instead of one), each with its own condenser, evaporator, and compressor. One circuit regulates the flow of refrigerant from the condenser to the evaporator based on the evaporator's heat load, while the other circuit has a constant refrigerant flow. Dual condenser cooling systems can be used as air conditioning systems or heat pumps.

• Provides serviceability and Longevity: For example, one condenser can be taken offline (or break) and the other is able to still maintain close temperatures needed for the space to still function.
• There are various systems that use different methods. Can include the use of multiple chillers instead of a single chiller.
• The system essentially uses and directs coolant in whatever way is most efficient given the load requirements and environment/weather.