Figure 1.
![HRU-WALL-100-25 compact recuperator and its dimensions in millimeters [11]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64706f9983f1392090d697be/j_acee-2019-056_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKMPLDCJRG%2F20260126%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260126T001915Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEGQaDGV1LWNlbnRyYWwtMSJHMEUCIHB%2BUwVEk5NFfziniAg1s96W%2F0F5nw6XFtT9KusvhUzBAiEAmYVTKBDxStZg1DtP7RoCRav0vnhN2Q2BZfs5j3TsGWYqvQUILRACGgw5NjMxMzQyODk5NDAiDDS1j7J3yn%2FuSNn4JiqaBdt19Bt7iEb%2BrZ3Uj%2F%2FaLNsElzYJaPoiuPfLdW%2BckjYF%2Fy5gEa3NjjbKO%2FDRx%2FpGTKmqMlbMZzrTkoW8ORw13C39JAtv2U3mTocGNwUEUT86zU5Gr31PymFAfff6Fi05RPE4QqgZyc2dQyz90KFqmg9h0B32p8QxaKYtLrV0wP1nPrXwnN%2FP%2BmJNVkH%2B7jAAj7%2FVb4PbhClJliheQLFjiHvRn5f%2Fido4QQFU609qTw%2B7y0t7wvMvPExWuEPE92deNE9MMUJmCK9Esl90Hxji2hPLYuyRSEspWz5MnuFleZcPtpLE%2F86JBRWWNssktYlc6u%2Bc9Rdx4QlYb36IMNfuljpmHi6J2iPmljv19S%2FlM7nEMuZSHhE8UDr86fhZ0NCFJ7IovWbIHkznTbQMDzLlD5dm6HCM%2B6m05UavU5zb5RLAo5hAd6cLhcf4IcrzevudoCTOsaeEv3qlvrpQvydzXB0fTtK5yZaAdCk5antRmopzoyyjwHPhb9iQYtF4l8E6bQElfps1qYRtYdA2HuXhl3T73o3iqpCRUYpq8JL1EWtKZtaXLoNXtjCIfjXa3PciZqWwhrO2tbv4W6gY2kvxLYvKt1g5LsW6R2LEm4srGi25YYvdqJ6MrWeSMnnr5x9MW%2FonWzd%2Fj%2BJJJ4qBnbrTVOaUXNEWO7BTUsW1DE97j7Q4KX1UW4Xz8h%2FqXP6S%2Fd8AZJOG5UWfwbJ5yzN%2FEmHlq12BtV1lf5SITOBFNEppz9ZNvP0Ey8zTF%2BMKpicuZ2znxWH6gE35zOMRHgvi5vrPDnQ3JAXX9ZQMopZb11nAtF2tDu2iIiXjoiqnjf2gZr4SrFtI0oyPN7aurJg1BrAlU49Uc%2B%2BTz3yjI7N5LsdEVJs2%2F%2FFRoHbri8U2mTC83NnLBjqxAVlFmoXFIuuvQHYp0fTeIhSrr7QfjwVWAH9IaGHwVzdQ0MgC%2F%2BUaaEyDHwNUIdI1ROLqblFnXLMNQdOF7J87%2BOBmj%2BFnOZgLIhsjjM2bVVBYECCD4TSZVHycqA5HZ0KYK66yNuFMU%2BJTFtaqvmI0QnQ4ILcrhlIUxV7PWqV%2BqEESRbCcL19rsXxU%2FI1PPY%2FieBrWekrVo3WzZLwKriUqU9QeECWvwWfvHYVKExS7EwHbAg%3D%3D&X-Amz-Signature=a03f4b60583b634bc381008741ec4b0fb37b43a03413ed8a0c2f4954ae9bb328&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Calculated averaged air flow volume rate for all fan speeds based on measurements for 0 Pa
| Air supply | 0 Pa |
|---|---|
| first fan speed | 9 m3/h |
| second fan speed | 16 m3/h |
| third fan speed | 28 m3/h |
| Air exhaust | 0 Pa |
| first fan speed | 8 m3/h |
| second fan speed | 14 m3/h |
| third fan speed | 29 m3/h |
Calculated supply efficiency for the tested working conditions
| Working conditions | Supply efficiency |
|---|---|
| third fan speed at balanced pressures | 64% |
| second fan speed at balanced pressures | 68% |
| first fan speed at balanced pressures | 79% |
| third fan speed at a natural pressure difference | 56% |
| second fan speed at a natural pressure difference | 47% |
Calculated exhaust efficiency for the tested working conditions
| Working conditions | Exhaust efficiency |
|---|---|
| third fan speed at balanced pressures | 73% |
| second fan speed at balanced pressures | 83% |
| first fan speed at balanced pressures | 85% |
| third fan speed at a natural pressure difference | 79% |
| second fan speed at a natural pressure difference | 93% |
Calculated averaged air flow volume rate for all fan speeds based on measurements for 7 Pa
| Air supply | 7 Pa |
|---|---|
| first fan speed | 19 m3/h |
| second fan speed | 22 m3/h |
| third fan speed | 36 m3/h |
| Air exhaust | 7 Pa |
| first fan speed | -8 m3/h |
| second fan speed | 6 m3/h |
| third fan speed | 25 m3/h |
Calculated averaged air flow volume rate for all fan speeds based on measurements for 4 Pa
| Air supply | 4 Pa |
|---|---|
| first fan speed | 14 m3/h |
| second fan speed | 20 m3/h |
| third fan speed | 32 m3/h |
| Air exhaust | 4 Pa |
| first fan speed | 2 m3/h |
| second fan speed | 12 m3/h |
| third fan speed | 27 m3/h |