Designing kitchen ventilation that works in really tight houses seems almost impossible.
That's why, in Passivhaus designs, where every cubic foot of air is accounted for, designers often use recirculating fans to remove the grease, and depend on the heat recovery ventilator to change the air. But this has been controversial too, as I noted inShould your kitchen have a recirculating or a direct-exhaust hood? I am exhausted just thinking about it.
However, it appears that we now have a definitive answer, in the form of new research from Shelly L. Miller and Ryan E. Militello-Hourigan from the Department of Mechanical Engineering, University of Colorado Boulder. They tested indoor air quality of nine tightly constructed homes, a library and a conventionally built home, seven of which were certified Passivhaus or PHIUS, and published their results asThe impacts of cooking and an assessment of indoor air quality in Colorado passive and tightly constructed homes.
The researchers brought their own induction hot plate and frying pan and overcooked a large Grade AA egg for six minutes. (Sorry about the "this is your brain on..."intro) "It should be noted that is a long time to cook a fried egg, and the emissions from this activity are likely higher than a normal fried egg. The goal was to produce substantial emissions that are within the range of normal cooking."
© Fig. 1. Short-term (20 or 30 min) PM2.5 average concentration after cooking for under each ventilation modes.
© Fig. 2 Number of hours each building exceeded NAAQS 24-hr limit after cooking test.
从房子漏水的传统是结果in fact the best, probably due to the higher infiltration rate of outside air.
The researchers conclude:The passive house concept can be an effective design approach to reduce energy use and improve thermal comfort, but it should not be assumed that this type of building has inherently good indoor air quality. Severe, but not atypical, cooking events drastically reduced the indoor air quality for many hours, and the temporary boost mode that many of the mechanical ventilators feature was ineffective at reducing PM emissions from the cooking activities. ...
- Install a fan that exhausts to the exterior. Period. AsProfessor John Straube put it once: "Recirculating range hoods don't solve the IAQ problem. It's like a recirculating toilet. The stuff just goes round and round and never leaves."
I also made some other suggestions after reading earlier research:
- Just stop putting gas into homes; induction cooktops work really well now.
- Engineer Robert Bean recommends that it be wider than the range, not more than 30 inches from the top, and against a wall. Oh, and the duct runs should be short and straight.
Kitchen stove in Sears Catalog Home built on Sanibel Island, Florida / Lloyd Alter/cc by 2.0
如果您在一百年前购买了一个Sears Home Kit，他们常常在房子的背面陷入困境的厨房范围。这有很多好处;他们可以避免通过在任何一侧打开通风，避免加热整个房子（这一个是佛罗里达州的Sanibel岛上）。如果火灾发生火，那么燃烧整个房子的可能性就不那么脆弱。也许我们必须开始考虑将我们的厨房范围放在烹饪摊位或利基。
Or perhaps we should just order in; this is all so difficult.