ENGINEERING – THERMODYNAMIC & HVAC CALCULATOR
Heat Recovery Efficiency
A precise tool.
What is the Heat Recovery Efficiency & How does it work?
Heat recovery ventilation (HRV) and energy recovery ventilation (ERV) systems capture thermal energy from stale exhaust air and transfer it to incoming fresh air, thereby reducing the heating or cooling demand of a building. The performance of these devices is expressed as a heat‑recovery efficiency, which quantifies how closely the temperature of the supplied air approaches the temperature that would be achieved with a perfect (100 %) heat exchanger. Understanding and correctly calculating this efficiency helps designers size equipment, estimate energy savings, and compare different ventilation strategies.
eta = frac{T_{text{sup}} – T_{text{out}}}{T_{text{exh}} – T_{text{out}}}times 100%
eta = heat‑recovery efficiency (%)
Parameters
Result
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Frequently Asked Questions
What is heat recovery efficiency?
Heat recovery efficiency measures how well a ventilation system transfers thermal energy from exhaust air to incoming fresh air, reducing heating or cooling needs.
How do I calculate heat recovery efficiency?
To calculate it, divide the temperature difference between the supply and return air by the temperature difference between the exhaust and supply air, then multiply by 100.
Why is heat recovery important in buildings?
Heat recovery reduces energy consumption by reusing thermal energy from exhaust air, lowering heating and cooling costs.
What factors affect heat recovery efficiency?
Factors include the type of heat exchanger, airflow rates, humidity levels, and temperature differences between incoming and outgoing air.
Can I improve my HRV/ERV system’s efficiency?
Yes, by maintaining clean filters, ensuring proper sealing, and using a balanced ventilation system to optimize airflow.
What is the difference between HRV and ERV?
HRVs transfer heat only, while ERVs also exchange moisture, making them suitable for climates with significant humidity changes.
How do I interpret the heat recovery efficiency percentage?
A higher percentage indicates better energy recovery; 100% means all thermal energy is transferred perfectly from exhaust to supply air.
Results are for informational purposes only and do not constitute professional advice.