Energy Recovery Ventilation vs. Heat Recovery Ventilation

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2020-08-18
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What’s the difference between ERV and HRV?

The ventilation system provides a comfortable living space by supplying clean fresh air from the outside while exhausting waste air from the inside.

The Heat Recovery Ventilation (HRV) unit are designed to enhance the heat exchange between these two air flows. In winter, warm exhaust air preheat the air supply as it enters the building. In summer, the warm air supply will be cooled by the exhaust.

The Energy Recovery Ventilation (ERV) unit also recovers heat. But, they also allow for moisture exchange when supply fresh air or exhaust waster air. then the humidity can be adjusted so that excessive drying can be prevented or mitigated, especially during the winter months. So,the energy recovery is a combination of heat recovery and moisture recovery.

 

ventilation system

 

Matrix Ceramic Core Heat Exchangers (HRV)

Matrix ceramic core heat exchanges deposit heat into a core by forcing air through it with a fan. The matrix face splits the airflow to maximise the surface area in contact with the core, facilitating more efficient heat transfer. The core itself is made of a ceramic material to allow for a greater amount of heat storage.

This heat is then recovered by periodically reversing the direction of the fan. When it is hot outside and cool inside, the supply air from outside will deposit heat in the core which will then be reabsorbed and removed from the system by the exhaust air when the fan changes direction. When it is cold outside and warm inside, the exhaust air being removed from the house will deposit heat in the core which is used to preheat the supply air from outside when the fan changes direction.

 

ventilation system

 

In the case of Vtronic VT501:

Two filters and the ceramic core are located inside the inner ductthe filters are designed to purify supply aie and prevent foreign object ingress to the heat exchanger and the fan.the ventilator generates a sound alarm reminding to clian or replace the filter every 90 days.

 

 

The matrix ceramic core heat exchanges are used to store heat from airflow, When it is hot outside and cool inside, the supply air from outside will deposit heat in the core which will then be reabsorbed and removed from the system by the exhaust air when the fan changes direction. When it is cold outside and warm inside, the exhaust air being removed from the house will deposit heat in the core which is used to preheat the supply air from outside when the fan changes direction.

 

 

Rotary Wheel Energy Exchangers (ERV)
Rotary wheel energy exchangers consist of a pure aluminium wheel with a honeycomb matrix of holes on the face as well as two channels which contain warm and cool air flows respectively. Heat transferred into the matrix by the warm air is later recovered with by the cool air once the wheel rotates between the two channels.

 

 

In the case of Vtronic VT260:
In cooler months, the warm exhaust air will transfer heat to the incoming cool air to preheat it. This increase in temperature allows the air to hold more moisture which results in a lower relative humidity. However condensation occurs in the exhaust channel which is transferred to the supply channel by the rotation of the wheel where it is reabsorbed by the incoming air. This recovery of humidity prevents the interior air from becoming too dry, improving its quality.

 

 

In warmer months, the cool air being exhausted from the building will intercept some of the heat and moisture absorbed from the incoming warm air, removing it from the system before it enters the interior and keeping the house cool on warmer days and minimising excessive drying of the indoor environment.