HVAC Systems
The goal for a Heating, Ventilation and Air Conditioning (HVAC) system is to provide proper air flow, heating, and cooling to each room. HVAC is sometimes referred to as "climate control" and is particularly important in the design of medium to large industrial and office buildings such as sky scrapers and in marine environments such as aquariums, where humidity and temperature must all be closely regulated whilst maintaining safe and healthy conditions within.
HVAC accounts for 40% to 60% of the energy used in U.S. commercial and residential buildings. This represents an opportunity for energy savings using proven technologies and design concepts.
HVAC systems have a significant effect on the health, comfort, and productivity of occupants. Issues like user discomfort, improper ventilation, and poor indoor air quality are linked to HVAC system design and operation and can be improved by better mechanical and ventilation systems. In existing buildings, envelope upgrades are often necessary to maximize comfort and energy efficiency, such as reducing envelope leakage.
The best HVAC design considers all the interrelated building systems while addressing indoor air quality, energy consumption, and environmental benefit. Optimizing the design and benefits requires that your mechanical system designer and your architect address these issues early in the schematic design phase and continually revise subsequent decisions throughout the remaining design process. It is also essential that you implement well-thought-out commissioning processes and routine preventative maintenance programs. This is good advice for both new and retrofit applications.
Criteria for a Quality HVAC System
An HVAC system should:
1. Be properly sized to provide correct air flow, and meet room-by-room calculated heating and cooling loads.
2. Be installed so that the static air pressure drop across the handler is within manufacturer and design specifications to have the capacity to meet the calculated loads.
3. Have sealed supply ductwork that will provide proper air flow.
4. Be installed with a return system sized to provide correct return air flow.
5. Have sealed return ductwork that will provide proper air flow to the fan, and avoid air entering the HVAC system from polluted zones (e.g., fumes from autos and stored chemicals, and attic particulates).
6. Have balanced air flows between supply and return systems to maintain neutral pressure in the home.
7. Minimize duct air temperature gain or loss between the air handler and room registers, and between return registers and the air handler.
8. Be properly charged with refrigerant.
9. Have proper burner operation and proper draft.