hydronic heating

How to ensure hydronic heating system efficiency

Wednesday, February 17, 2016

Hydronic heating systems continue to gain traction in Canada due to their high level of versatility, energy efficiency and comfort, which is a big plus for commercial buildings looking to lower costs and meet sustainable goals, and also for the growing population of Baby Boomers looking to retire to cozier, less drafty homes, cottages and seniors residences.

Yet, in order for such systems to run efficiently, components have to be matched and sized correctly. Such systems also have to be accurately maintained. Yet, many mistakes are made during the installation process, resulting in inefficiencies and unhappy building owners.

Here, Tim Rickards, who specializes in the hydronics field, designs and specks systems, and trains contractors, explains how to ensure a hydronic heating system runs effectively.

What are some key requirements of system efficiency?

A hydronic heating system is composed of three basic components: the boiler, circulators and pumps, and convectors, such as fan coils, floors and radiators. Controls and venting can be other components. Equipment that is properly sized results in a smart system design that saves time and effort, but initial consideration should be given to the boiler. Contractors are often worried this component will be undersized, but a bigger boiler isn’t always better. If a boiler is too large, it will cycle too frequently, wasting fuel with each cycle and reducing the life of the system.

Now, people are more interested in saving the environment and working with contractors to make sure sizing is done correctly. Why do you want to spend more money on a bigger boiler when you don’t need it? It also causes problems and pollutes the environment. Knowing the heating requirements of a building is vital information that will help contractors choose the right boiler for the job.

With radiant in-floor heating, a constant battle in the industry is knowing the difference between using a floor to heat a home versus warming a floor. With complete in-floor heating, floors never feel warm until the coldest day of the year. When a home is designed to make all the floors warm, the house will overheat, an uncomfortable and wasteful option. Yet, if a warm floor is applied to one room and then mixed with forced air, the forced air will shift the excess heat throughout the home. A contractor must first ask which application he or she is using because this knowledge will affect how the floors are controlled. A heating application will result in a floor that is controlled with a room thermostat; however, a floor warming application mixed with forced air requires a flap sensor control.

Many mistakes are located in the mechanical room with the way hot water is distributed around the building, such as through pipes where air can be trapped in the lines, preventing heat from getting out to the space.

The use of better controls and modern piping practices can also produce significant savings up to 30 to 40 per cent fuel in cubic metres of gas. Just by re-piping boilers in primary and secondary versus parallel, can save 15 to 20 per cent energy. Matching water temperature to outdoor temperature, known as outdoor reset, saves another 15 per cent. Couple these practices with modern boilers and another 10 to 15 per cent energy is saved.

How should a hydronic heating system be maintained?

Once all the components have been sized and matched appropriately for the job, the overall system must be maintained at least once a year. To begin, it is imperative that contractors follow a manufacturer’s recommendations on upkeep and cleaning cycles. Even dependable boilers require a certain level of maintenance that can mean the difference between a long life or a substantially shorter one.

Old boilers were like driving a Chevy—a big bullet proof tank. Now, we’re driving wall hung boilers like a Ferrari; you have to maintain them and keep them tuned up in order to maintain the efficiency and reliability. As you increase efficiency, it comes with more maintenance.

Modern boilers require the bulk of care because they extract a lot of heat from the flu gases, which condense in the heat exchanger. With old style boilers, manufacturers would try to ensure that didn’t happen, so the efficiencies were in the low 80 per cent. Now, government mandates higher efficiencies, which means more maintenance. Manufacturers are aiding this process by calibrating new boilers for optimal performance, employing rigorous in-factory quality control tests and increasing technical support.

Modern boilers need to be kept clean and adjusted correctly. If this doesn’t happen, they destroy themselves. All these new products need more care than the old boilers, and if they don’t get proper care, building owners will be left cold on a February morning.

Tim Rickards is former co-owner of The Hydronics Group and now technical sales representative for The Master Group, the largest independent HVAC-R distributor in Canada.

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