Heat Recovery in HVAC: Cutting Energy with Air-to-Air

Why Ventilation Wastes Energy

B建筑需要新鲜空气，但排出已调温的室内空气并引入未处理的外气，会浪费大量冷暖能源。寒冷时进风需加热，炎热时进风需冷却。空气-空气热回收填补了这一缺口。

How Air-to-Air Recovery Works

空气-空气换热器在不混合两股气流的前提下，于排出排风与流入新风之间传递能量。显热回收仅转移热量；焓（全热）回收还转移湿度，在潮湿气候中很有价值。

Two Common Designs

• 板式换热器：铝或聚合物固定芯体，简单可靠，适合两股气流必须完全分离的场景。
• 旋转轮：带除湿涂层的旋转轮，蓄存并释放热量与水分；效率高，但气流间有少量交叉泄漏。

Where It Pays Off

回放在换气率高的建筑（学校、办公楼、医院、实验室）中最有价值。寒冷气候下，回收排风热量可将供暖需求削减三分之一以上。

Sizing and Control Tips

• 使效率匹配气候：寒冷地区更高，并与风机能耗相平衡。
• 在过渡季使用旁通风阀，避免阻碍免费供冷。
• 对极寒站点指定防冻保护，例如预热或排风再循环。
• 保持过滤器清洁；污垢是性能下降的主因。

Bottom Line

对多数通风建筑而言，空气-空气回收是回收期最短的节能改造之一。硬件成熟、维护量低，且节省在每一个冷暖季反复发生。

常见问题

How does air-to-air recovery reduce HVAC energy?
It transfers energy from the outgoing conditioned exhaust to the incoming fresh air, so the heating or cooling system only makes up the remaining difference rather than conditioning 100 percent outside air.

What is the difference between sensible and total recovery?
Sensible recovery moves heat only. Total, or enthalpy, recovery also transfers moisture, which is valuable in humid climates where both temperature and humidity loads are high.

Which design suits buildings better, plate or rotary?
Plate exchangers are simple, leak-tight, and good for moderate airflows. Rotary wheels suit larger volumes and can recover humidity, at the cost of slight stream carry-over.

Does recovery also improve comfort?
Yes. By pre-conditioning ventilation air, it stabilizes indoor temperature and humidity and reduces the size of the heating and cooling plant needed.

常见问题

How does air-to-air recovery reduce HVAC energy?

It transfers energy from the outgoing conditioned exhaust to the incoming fresh air, so the heating or cooling system only makes up the remaining difference rather than conditioning 100 percent outside air.

What is the difference between sensible and total recovery?

Sensible recovery moves heat only. Total, or enthalpy, recovery also transfers moisture, which is valuable in humid climates where both temperature and humidity loads are high.

Which design suits buildings better, plate or rotary?

Plate exchangers are simple, leak-tight, and good for moderate airflows. Rotary wheels suit larger volumes and can recover humidity, at the cost of slight stream carry-over.

Does recovery also improve comfort?

Yes. By pre-conditioning ventilation air, it stabilizes indoor temperature and humidity and reduces the size of the heating and cooling plant needed.