Efficient use of energy is both a design and operations issue. In order to achieve a total reduction in facility energy use, both the efficiency of a system and conservation of energy must be considered. For example, a highly efficient HVAC system will reduce the cost of operation, but if it is operating during unoccupied times, the savings will be wasted on the energy used for the additional operating time.
Three principles direct the design of an energy-efficient facility. Sound energy design will strive to do the following:
- Select components and equipment that provide efficient use of energy.
- Investigate ways to reuse waste energy that may occur during the normal course of operation.
- Seek ways to minimize the use of energy by limiting unnecessary consumption of energy.
How these principles are accomplished depends on conditions specific to an individual facility. Many factors must be considered before deciding on specific energy-savings implementation. Factors such as the total potential energy savings, the cost of implementation, the life-span of the design, and the cost of ongoing maintenance, all factor into the payback of an energy-saving design.
Below is a sample checklist of energy savings criteria used to evaluate potential savings:
- Efficiency of motors
- Efficiency of light fixtures (lamp type)
- Use of skylights in certain areas to reduce dependence on artificial lighting
- Efficient use of gas, electric and steam in equipment
- Efficiency of equipment (energy star rating)
- The reuse of “waste heat” where possible, such as from refrigeration systems and air compressors
- Use of variable frequency drives (VFDs) on fans and pumps where feasible
- Use of an energy-management system on exhaust systems, coupled with VFD’s on exhaust fans
- Utilizing existing central utilities systems such as steam, chilled water, and refrigeration
- Efficiency and feasibility of different refrigeration systems (halocarbon vs. ammonia)
- Air vs. water cooled condensers for refrigeration and air conditioning systems
- Lighting controls (occupancy sensors, timers)
- Efficiency of ventilation control
- Efficiency of HVAC controls
- Building automation systems
- Efficiency of water heating systems
- Efficiency of plumbing fixtures (water use reduction)