Efficient heating system design with boiler controls and sensors
How can controls and monitoring help to improve the efficiency of a commercial heating system?
Built-in boiler controls have come a long way from simple on and off settings. Today, they offer more complex programming options which are not limited to controlling only one boiler.
Further benefits can be gained by combining them with external tools such as space temperature sensors. Considering this option and other factors in the building, such as the thermal envelope and usage of different areas, offer an integrated approach to heating efficiency.
This way, comfort levels are maintained, which has a positive effect on the wellbeing and productivity of building occupants. Maximising the use of commercial boiler controls has benefits beyond heating costs.
Why should I design a commercial heating system with heating zones?
Planning of a commercial heating system should consider differences in use of parts of the building.
- Kitchens for example benefit from heat contributors such as ovens and hobs, lowering their heat demand
- Corridors on the other hand do not require constant heating, as they are mainly used to get to another part of the building
It is essential to divide a building into different heating zones to avoid unnecessarily heating or overheating areas.
The required energy is effectively minimised which reduces the costs to warm the building - heat is provided when it is needed, where it is needed, and at the right intensity.
How can I monitor temperature and free contributors?
For this purpose, internal space temperature sensors are useful.
These
- should be positioned in carefully selected locations away from direct sunlight or other factors that affect measurements
- not only monitor the performance of the heat generators and the various heating circuits
- can also track “free contributors” such as solar radiation, especially where glass is present, heat generated from the occupants and by internal processes (e. g. cooking, internal lighting) and IT equipment (servers and computers etc.)
What influence do the design and layout of a building have on thermal properties?
There are lots of factors to examine when setting the boiler controls.
- Thermal inertia: How quickly does a space respond to heat input
- Low thermal inertia: e. g. office with low ceilings – allows the space to heat up quicker and reduces the required start time before occupants arrive
- High thermal inertia: e. g. places with large volumes of air (e. g. churches), required heat up time is high.
- High ceilings = poor heat distribution unless suitable equipment is installed to solve this issue
It is necessary to calculate an adequate time to switch on the boilers in the morning which take the above factors into account.
- Heat loss
- occurs on surfaces which make up the building envelope which separates a building from the outside (walls, floors, roof, windows etc.) and gaps in it where cold air can come through
Heat loss can be considerable especially in the winter months with low temperature and winds. It is necessary to monitor the external temperature at any given time to estimate the heat loss from the building.
Built-in boiler controls – taking care of many things at once
Modern boiler controls can ’multitask’. They can optimise the heat output of heat generators, heating circuits, and also control the heating. However, lack of knowledge on the user’s side means they are often not used to their full advantage.
What basic boiler control modes are available?
Correct setup helps to improve efficiencies and extend the lifetime of the products, as it ensures even use across the installation. In multiple boiler arrangements, the boilers can be set to operate in different modes:
- Unison control - the controller attempts to hold as many boiler modules firing at the same time to match the base load of the building. The aim of this setting is to have them all modulate to more efficient low fire together.
- Cascade control - the controller attempts to match the base load with as few boiler modules as possible. Each method has its own merits dependent on the hydraulic configuration local to the boilers.
Looking beyond the boiler
To make the best use of modern technology, the heating system should be looked at as a whole. Efficiencies can be improved by using advanced boiler controls, sensors, mapping out high/low use areas of a building, and considering heat up time. This benefits not only carbon emissions and energy costs but can also extend the reliability and lifetime of a system.