How can you improve the energy efficiency of a commercial, industrial or institutional building?
By switching from incandescent to LED bulbs, of course!
In fact, the trend is towards LED lights. According to Hydro-Québec, LED bulbs last 15 times longer and consume 70% to 90% less energy than incandescent lights.
Let’s take it a step further.
A question of heating
Although the exact percentage of electricity used for lighting is difficult to estimate and varies from company to company, it is normally significantly lower than the percentage used for heating and cooling. (For reference, Hydro-Québec allocates 54% of residential energy consumption to heating and cooling, and only 5% to lighting).
This article offers food for thought on reducing energy consumption for commercial and industrial building heating, while presenting electric infrared heating as a heating option for reducing energy consumption in certain environments and situations.
How to improve energy consumption in commercial and industrial heating systems?
First of all, to use a residential analogy, if you want to reduce your heating consumption, all you have to do is
- Well-insulated walls and windows,
- Opt for efficient heating technology,
- To heat only the parts used and
- Heat only while the parts are in use.
This formula also works for the commercial and industrial sectors. However, since commercial and industrial buildings are not always divided into rooms like a house, “rooms” should be replaced by “sections”.
Let’s take a look at how to apply this formula to large commercial and industrial buildings.
i. Insulation (heat retention)
Insulation is the first factor to be considered for reducing heating-related energy consumption when constructing a building. In order to better target the practices that can improve the energy efficiency of heating, which applies to both new and existing buildings, insulation will not be dealt with in this article.
ii. Heating technology (efficient heat production)
Heating technology includes the type of energy transfer: convection, radiation, conduction, as well as the type of energy used (electricity or natural gas) to produce the heat.
How to choose the right type of energy transfer?
Among convection, radiation and conduction, only convection and radiation are considered for heating a building with a large volume.
Reminder:
Convection is the transfer of energy between an object and its environment, due to air movement. In the case of building heating, this is referred to as forced convection, since a fan is used to accelerate heat transfer.
Radiation is the transfer of energy through the emission of electromagnetic radiation. When heating a building, we speak of infrared radiation, since this is the section of the electromagnetic spectrum with the wavelength most conducive to heat transfer. (Discover infrared in this article: Infrared – Technirep )
When does radiant heating become more efficient than convection heating??
Radiant heating is more efficient than convection heating in 4 situations
a. When air changes are significant.
According to ASHRAE/IES standard 90.1, 9.4.6.1 Radiant heating systems should be considered instead of convection or warm air heating systems for heating areas that experience infiltration loads greater than 2 air changes per hour.
Considering that warm air moves with air currents, it’s inefficient to heat a building with a large change in air by convection, since the heat is lost. Radiation is more efficient in this situation, since it takes place in a vacuum and is not affected by air.
b. When a building has a high ceiling.
According to ASHRAE/IES standard 90.1, 9.4.6.2 Radiant heating systems should be considered for areas with high ceilings, for spot heating and for other environments where radiant heating may be more energy-efficient than convection or warm air heating systems.
Since warm air has a lower density than cold air, the warm air rises in the air volume (building in this case) and makes way for the cold air. In the case of convection heating, this means heating the entire volume of air in the ceiling before heating the volume of air near the floor. On the contrary, radiation heats surfaces directly, including the ground and people, in the case of a building.
c. For zone heating
Radiant heating is not only more efficient for heating one area of a large building, it’s also the only method of heating a single area of a building. Infrared radiant heating heats people in a work area without heating the rest of the building.
d. For occasional heating
Radiant heating can be used to heat a workspace punctually, without the need to preheat the space as with convection. Radiant heat transfer is instantaneous.
A concrete example of where infrared is more efficient than convection heating
Significant air changes. |
– Loading dock – Garage – Vestibule – Railway station |
High ceiling |
– Warehouse – Soccer field and sports stadium – Church – Garage – Factory – Distribution center |
Zone heating |
– Workstation – Stands |
Spot heating | – Any space used occasionally |
How to choose the right type of energy
In the case of convection heating, electricity and natural gas each have their advantages. However, in the specific case of infrared heating, electricity is more efficient. Let’s find out why.
A simple question of yield.
Electric radiant infrared heaters with lamps have a higher radiation efficiency than natural gas radiant heaters. Electric radiant heaters can achieve a radiant efficiency of around 96%. Gas-fired appliances, on the other hand, have a radiation efficiency of around 50%.
Note: Do not confuse radiant efficiency with energy efficiency. An electric radiant heater is 100% energy efficient, since 100% of the energy is used for the heating function. In comparison, a unit heater uses part of the energy to turn the fan that pushes the hot air through. A radiant efficiency of 96% means that 96% of the energy used is converted to radiant heating, while 4% is converted to convective heating.
Electric radiant heating | Natural gas radiant heating |
Approx. 96% radiation efficiency – 96% of energy converted to radiation and 4% to convection |
Radiation efficiency around 50%. – 50% of energy converted to radiation and 50% to convection |
Contents: heating technology and energy
Electric radiant heating is most effective for buildings with high air changes, buildings with high ceilings, zone heating and spot heating.
iii. Zone heating (heat only the sections used)
An energy challenge for many commercial and industrial buildings is to heat an entire building when only one section is in use. This is a concrete example of energy waste.
Two options are available to reduce this energy waste.
Setting up sections
Similar to house walls, sections can be created (temporarily or permanently) in a large building to conserve heat and heat only the sections used.
Zone heating
When it’s not possible to install temporary or permanent walls to retain heat between sections, zone heating can significantly reduce energy consumption.
How does zone heating work?
Radiant heating heats a single area of a space. Since infrared doesn’t heat the air like convection heating, but rather the surfaces onto which the rays are directed, it’s possible to direct the rays to the sections being used and create a comfortable space without needlessly heating an entire building.
Tip: To reduce energy consumption in this context, a control system that allows zone modulation of heating units should be planned into the design and installation of the heating system.
iv. Heating management (heat only at the right moment)
This is mainly due to excess energy consumption at night and during other periods when the building is not in use. Similar to the idea of only heating the sections in use, heating only during the periods when the building is in use significantly reduces energy consumption. There are two challenges to improving energy management.
Manual temperature control
Many heating systems only allow manual temperature control. Out of simplicity or forgetfulness, the temperature is often left at a fixed high level even when the space is not in use, unnecessarily increasing energy consumption.
Tip: To reduce energy consumption in this context, a control system that allows zone modulation of heating units should be planned into the design and installation of the heating system.
Need to preheat the building.
With forced-air heating, it’s not always possible to significantly reduce the temperature of a building during periods of non-use, since the building’s preheating period is too long to allow people to quickly find a comfortable space.
Radiant heating offers a solution to this challenge. With an immediate feeling of warmth, this method of heating allows you to turn the heating system off completely when the space is not in use, or to lower the thermostat to between 5 and 10 degrees Celsius for spaces where you want to avoid freezing and simply turn on the heating when the space is in use.
Contents: heating management
By combining a radiant heating system that provides the sensation of immediate warmth with control adapted to the building’s needs, with one or more control options such as a timer, thermostat, presence detector, clock, etc., it is possible to heat only when the building is in use, and considerably reduce heating costs.
Installation of an electric radiant heating solution
Electric radiant heating is the most efficient heating technology for buildings with high air exchange, for buildings with high ceilings, for zone heating and for spot heating.
Here are a few things to consider when setting up a successful electric radiant heater.
- Choosing the right type of electric radiant heater.
- Infrared tube devices vs. infrared lamp devices
- Power
- Reflector angle
- Choosing the control options best suited to buildings and needs
- Thermostat, potentiometer, timer, BMS signal, etc.
- Position radiant heaters in critical areas for zone heating.
At Technirep, our team of experts will guide you in setting up the system best suited to your needs.
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How do you plan to reduce your energy costs over the next 12 months?
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