hvac

Central heating, ventilation, and air conditioning (HVAC) systems regulate temperature, ventilation, and humidity levels to ensure the physical comfort of occupants in most commercial and industrial buildings. Central HVAC systems come in a variety of different types; purchasing a system with a high efficiency rating can save you up to 35 percent on energy costs. In addition, HVAC controls, economizers, thermal energy storage systems, and other efficient HVAC technologies can save you even more on energy costs.　

Typical Applications

Commercial buildings commonly choose several types of systems based on the space conditioning needs of different systems. A constant-volume (CV) system might cool the interior, which has relatively uniform cooling requirements while a VAV system conditions perimeter areas which have variable requirements. Where precision control is required (e.g., hospital operating rooms), custom single-zone air handlers may be used. In large facilities, which have widely varying requirements, flexibility is extremely important.

Typical Applications of Central HVAC System
Building Type	Type of System
Office Buildings (low rise)	VAV; or CV in the core, and hydronic at perimeter
Office Buildings(high rises)	Central CV system for core, VAV or hydronic at perimeter; dual duct is common in existing buildings
Department Stores	Multiple CV or VAV air handlers
Universities	Central steam boiler and chiller plant with CV, VAV or combined air-water systems at each building
Schools	Central boiler and chiller with CV or VAV air handlers serving individual common areas, and hydronic or combined air-water systems in classrooms
Hospitals	Large chiller, boiler plant (steam common); separate CV systems for critical areas; CV or VAV for common areas; hydronic and combined air-water in patient rooms
Hotels	VAV for common areas; fan-coil units in guest rooms for individual temperature and humidity control
Assembly Theaters	Multiple VAV air handlers
Librabries, Musuems	Multiple CV air handlers, with precise humidity and temperature control

Problems Generally Found in Chiller Plants

Space cooling for buildings in Hong Kong accounts for a significant part of the energy consumption in the building sector. Electricity consumption by a central air-conditioning chiller plant may be up to 30% of the total energy consumed in a building. Inadequacy in wrongly estimation of building cooling load or misuse of “safety margin result in oversizing a plant is also common in Hong Kong. Therefore, setting up a quality monitoring system for a chiller plant will help plant operators to diagnose problems and optimize plant performance. Unfortunately, reliable transducers and metering equipment at are essential to properly maintain plant and to monitor performance are absent or of inadequate accuracy for temperature, pressure, water flow rate and electrical input. Particular attention should be paid to the following parameters for accurate data to be obtained for energy saving analysis:-

Tips for Efficient Operation and Maintenance

Regular maintenance is needed to keep equipment clean and functioning properly and to avoid wasting energy. The following items should be part of a maintenance program: