Comparing Heat Exchangers For Heat Recovery Ventilation

Copyright (c) 2015 Matt Reardon

In ventilating a room using the heat recovery method, the only medium involved is air. Plated exchangers are some of the best devices for this. They have a large surface area because many tiny plates are stacked together. This further makes them energy efficient and fast. There are however, other different types of exchangers. Here is an examination and comparison of them.

Heat Recovery Wheel

Put simply, it is a rotating wheel controlled by a motor. Air is run through the wheel, where it is cooled/heated up.

It is set up in a way that the two streams of air lie next to each other, but flow in different directions. They pass through one half of the rotating wheel where the exchange takes place. It is sometimes called a thermal wheel.

It transfers heat directly, making it very effective and efficient.
Its speed can be adjusted and the route of the incoming air can be diverted.
The controlling motor can be stopped so heat exchange is stopped whenever necessary.

However, there are higher chances of the two sets of air coming into contact as the pass through one half of the wheel.

Heat Recovery Pipe

A series of pipes are placed In the separate vents carrying the fresh and stale air. The cooling substance absorbs the heat from the stale air, vaporizes and condenses over the fresh air releasing the previously absorbed heat in the process.

At high temperatures, the cooling substance will not condense, making the system useless. One example of a cooling agent is silica gel. When temperature drops are inevitable, like during winter, the best way to stop the freezing is to block off the incoming air, warm up the central passage and let the fresh one in through the warmed air first.

Pipes can transfer heat over long distances and are simple to operate. Copper pipes offer the best conduction of heat.

Wire Heat Exchanger
Wires, being thinner than pipes, have an even greater surface area.
They can be fixed in many discreet locations.
They are two dimensional, so no cleaning of vents is required.
There's no mixing of air when you use the wires.

Cross-plate Heat Exchanger

It works best in counter flow systems. It is a plated ventilator, made of a series of aluminium or steel plates. They are placed in different positions as heat passes through the plates from the exhaust air to the air being let in.

The air coming into the exchanger has to be at least zero degrees. Any lower temperatures and substances inside the system might freeze up and block the entire system.

Apart from Australian standards, the heat exchangers may strive to meet other standards like Germany's Passivhaus.

Consider getting a ventilator with filters so pollen, dust or radioactive particles don't get in your system when you inhale.

The American Society of Heating, Refrigerating and Air Conditioning Engineers recommends at least 0.35 Air changes per hour in a home. Find a skilful installer to fit a heat recovery ventilation system in your home so your indoor air quality improves.


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Matt Reardon works at Mould Buster. He is fascinated by the workings of mechanical ventilators. Mould Buster is a passionate team whose level of dedication is proven by the exemplary work they have done in many Australian Homes. For more information about BCA and the AS complied visit http://mouldbuster.com.au/ .