Scope of Modern HVAC
Modern air conditioning is critical to almost every facet of advancing human activity. Although there have been great advances in HVAC, there are several areas where active research and debate continue.
Indoor air quality is one that directly affects us. In many countries of the world there is a rapid rise in asthmatics and increasing dissatisfaction with indoor-air-quality in buildings and planes. The causes and effects are extremely complex. A significant scientific and engineering field has devel- oped to investigate and address these issues.
Greenhouse gas emissions and the destruction of the earth’s protective ozone layer are concerns that are stimulating research. New legislation and guide- lines are evolving that encourage: recycling; the use of new forms of energy; less energy usage; and low polluting materials, particularly refrigerants. All these issues have a significant impact on building design, including HVAC systems and the design codes.
Energy conservation is an ongoing challenge to find novel ways to reduce consumption in new and existing buildings without compromising comfort and indoor air quality. Energy conservation requires significant cooperation between disciplines.
For example, electric lighting produces heat. When a system is in a cooling mode, this heat is an additional cooling load. Conversely, when the system is in a heating mode, the lighting heat reduces the load on the building heating system. This interaction between lighting and HVAC is the reason that ASHRAE and the Illuminating Engineering Society of North America (IESNA) joined forces to write the building energy conservation standard, Standard 90.1–2004, Energy Standard for Buildings Except Low-Rise Residential Buildings4.