Heating and Cooling

The HVAC System

The heating, ventilation and air conditioning (HVAC) components of a commercial building work together to control its temperature, ventilation and humidity. In a typical Canadian office or industrial building, boilers, electric heat coils or heat pumps are used to generate heat; chillers, air conditioners or cooling towers remove undesirable heat; and a ventilation system provides fresh air to ensure good indoor air quality. The origins of today’s HVAC processes date back to second-century Rome’s hypocaust, a system of centralized heating that forced hot air and smoke from the furnace through enclosed chambers in the home’s walls and floors.

Commercial HVAC systems bear some resemblances to small-scale residential heating and cooling processes in that both use the same general principles and technologies. However, one obvious difference – size – creates unique challenges for commercial buildings. For example, most offices contain a considerable amount of office equipment including computers, photocopiers and printers, all of which generate significant amounts of heat. Workers doing light office work are like free-range furnaces, each giving off 115 watt-hours of heat every hour. Glass-clad office towers themselves absorb large amounts of energy: within one hour and for every square metre of glass, the sun can create up to 650 watt-hours of heat gain. And because a greater number of air contaminants may be present in the workplace, ventilation takes a critical role in these buildings.

Because every component of the HVAC system plays a specific role in the environmental wellbeing of a building, each will be described separately (below).