The determination of a chiller’s cooling capacity, often expressed in tons, is a fundamental calculation in HVAC system design. One ton of cooling is defined as the amount of heat required to melt one ton (2000 lbs) of ice at 32F in 24 hours. This translates to 12,000 British thermal units per hour (BTUH). For example, a system requiring the removal of 60,000 BTUH of heat would necessitate a five-ton chiller (60,000 BTUH / 12,000 BTUH/ton = 5 tons).
Accurate sizing of a chiller is critical for both operational efficiency and cost-effectiveness. An undersized chiller will struggle to meet cooling demands, leading to uncomfortable conditions and potentially damaging equipment. Conversely, an oversized chiller will operate inefficiently, cycling on and off frequently and incurring higher energy costs. Historically, estimations relied on simplified rules of thumb, but modern practices emphasize detailed load calculations considering factors such as building size, occupancy, insulation, and equipment heat gain.
