Heating Systems in Building
Heating, ventilation, and air conditioning (HVAC) technology helps in controlling the indoor environmental conditions of residential and commercial structures to provide thermal comfort and improve air quality. The use of an energy-efficient HVAC unit not only has a major impact on cost savings in the long run but also improves the health and productivity of the household.
Different factors help to improve the energy efficiency of an HVAC unit, including the type of system you have to how the system is maintained. Here are a few optimisation tips on having a considerable impact on energy efficiency savings with the HVAC systems of a building.
Keep a Check on Heat Losses from the building
Depending on the difference between the inside and outside temperatures, heating or cooling equipment, when in constant operation, maintains the inside temperature at a comfortable level. This they do by adding or removing the exact heat amount necessary to achieve the required temperature.
Steps towards Minimizing these Losses:
- Ensure better insulation of walls and roof to keep a check on heat radiation through conduction and dissipation
- Make your doors and windows with heat-insulated materials
- Ensure proper treatment of cold bridges (door and window frames, pillars or beams, etc.)
- When cooling is needed, use sun-screening devices to check solar radiation
It is wiser to adopt these actions when designing a new building and thus less expensive than if done on existing buildings.
Do Not Use Heating and Air Conditioning Simultaneously
For better energy efficiency, implement control systems with default settings that are perfect for the building, which do not operate heating and cooling systems simultaneously and can completely close part of the distribution circuit. Hence, one can use time switches to switch on and off HVAC systems at certain times of the day, such as before and after the start of a shift, programming in for public holidays, all of which go into reducing annual running time. Intelligent time switches are available that work out the optimal operating period and reduce the operating time significantly.
Avoid Improper Use of Heating Systems with the Following Tips
In the case of structures with commercial, administrative or industrial activities, the temperature should not cross 20°C to 22°C inside the rooms. Hospitals and health centres have higher temperature settings and gymnasiums and sports centres have possible colder ambient temperatures.
Keep a check on the opening of windows (both in cold and hot weather) or have your heating or cooling systems dependent on closed windows.
Optimise the Heating Systems to Make it Economical
There are two types of heat generators – individual systems and centralised systems.
Individual Systems: In this type, electric radiators such as convector, radiant or blower are used to separately heat each area of the building (rooms, office, etc.). Despite converting all the energy into heating the spaces (100% efficiency), the heating system is not that economical. To make it economical, there has to be control of the system to switch off the heating units when the space is no longer used.
Centralised Systems: There are two units in centralised systems – a heat generator (boiler) and a distribution system. The purchased heat from a supplier is delivered using hot water pipes and billing is done using thermal metering. Or else, a boiler present in the building is used to generate thermal energy. Greater efficiency is achieved using a recently designed boiler that is adjusted by trained personnel. Regular checking of the CO2 level and the temperature of the exhaust fumes help in measuring the efficiency level, irrespective of the kind of fuel used.
Depending on the source of heat, heat pumps are used either alone or along with a boiler. If the heat source is the surrounding air, then it is not possible to use the pump below a specific temperature due to the formation of icing. The widely used heat pumps are the “Air-Water” or “Air-Air” type during mid-season and the boiler in the coldest periods. The subterranean water may also be used as a source of heat, if available. In this case, the “Water-Water” heat pumps are used with a wider range of use as they are not dependent on the outside temperature.
There are two difficulties to using solar heating – first, it requires the right orientation of the solar panels for maximum exposure, and next, heat availability is subject to weather conditions. Hence, solar heating is best used as a supplement to heating systems.
Optimisation of Heating Circuits
A centralised heating system uses water pipes or air ducts to distribute thermal energy all through the various spaces of a building. To improve energy efficiency, it is important to reduce heat loss occurring along the pipes. This is achieved by insulating the water pipes or air flues, mainly in the unheated spaces (boiler rooms, ducting, service areas). Energy can also be saved by the introduction of zoned heating in which multiple thermostats control the different zones.
Optimisation of Heating Control
The heating control system must be so designed as to ensure the occupant’s comfort while cutting down energy consumption to a minimum. During normal operation, all of the spaces within a building must be kept at a comfortable temperature. However, when the building is not in use (nights, holidays, weekends), the temperature can be lowered by a few degrees.
Factors Needing Programming for Better Optimisation
Heating has to be turned on a few hours before the arrival of the occupants, and it may similarly be turned off just before they leave. It is worth the effort to fine-tune these periods to save on energy over time.
Wherever possible, regulating the temperature of various spaces of a building will help to prevent the heating of rooms that are either used occasionally or remain unused.
Adjust the temperature setting for each room, which would help in improving the user comfort significantly. Finally, keeping tabs on the external climate (temperature, sunlight, wind) would help in estimating the loss of heat from the building.