http://greendreamgroup.libsyn.com/this-house-sucks-but-not-very-har...

Check out this interview with brilliant scientist Brett Singer (seriously, he's a genius) from Lawrence Berkeley National Laboratory on our misconception about worst case CAZ Depressurization testing.

Tags: bpi, brett, case, caz, podcast, singer, testing, worst

Views: 1271

Reply to This

Replies to This Discussion

Even when gas stoves DO have exhaust fans they capture a small % of the combustion products. Note when a boiling pot is on the outside burners, most of the steam bypasses the exhaust hood. Inside burners get more of the exhaust. Even with 250 CFM the face velocity is way to small to capture all that much. 

solution - stoves need to be enclosed on three sides. NO one makes a stove like this but they should. This will more than double the face velocity an improve capture. Stainless side panels would do it and also eliminate splattering on adjacent counter tops. 

Good point. Now, assuming all of us here agreed, whom do you think we will win over first:
Appliance manufacturers or my wife?

Decades of experience in the Culinary realm give me a slightly different perspective.  It is the capture area of the hood that is of significance.  Installing sides will never go over, but if the hood were required to extend some predetermined amount beyond the cook surface and coupled with an appropriately sized fan motor, I believe the dynamics would fall into an acceptable range.

Hi Jim, just to add to your example from another perspective, a capture hood should also be more than a flat surface with an exhaust hole in the middle and skirting around it.  Take for example the fireplace industry that has to produce a draft without the fan.  By tapering the combustion chamber up to the flue there is a gradual acceleration of the air flow and less turbulence.  I suspect a little more air flow engineering as opposed to aesthetics would add to the effectiveness of hood design.

We must remember that the fan is not pulling the air from above the cooking surface up into the exhaust, just creating a low pressure zone in the vent so that the surrounding higher pressure can push all of that air into the little hole (just like a fireplace).

Bud

Actually engineering the flow would make sense. Maybe they need to attach the hood to the pot lid; now there is totally new paradigm.  Air jets blowing upwards around the edge of the cooktop would help also. After all that, there is still a need for some reasonable velocity to contain the products of combustion on the gas stove, the steam and smoke.  Apart from adding more flow, we haven't progressed at all in kitchen exhaust. 

Lizzy bought one of those NuWave induction stoves.  I've always hated electric and loved gas.  

I guess I have bias against induction that I wasn't aware of because even though there are all types of reviews raving about induction, experiencing it in person left me shocked.  (And I try to be open to having my schemas disrupted!)

In my mind cooking with gas is done.  If you haven't tried induction cooking, try it.  If you have tried it, and see any reasonable argument FOR gas, I'd be interested to hear it. 

Very interesting. Brett did a good job of explaining complicated subject and boiling down (pun intended)  points.

my favorite was "If you are going to do test that is going predict an unlikely event will happen then you need to do allot of monitoring to see if this event will happen"

I do not think we will see any changes anytime soon for CAZ but the podcast was a good refresher on the dangers of the gas stove top that I can take forward. I am glad that cfm in still equals cfm out

It also brings forward to me the need for mechanical ventilation. Many problems can be eliminated through dilution.  A good balanced ventilation system designed for the applicable climate is still one of the best things we can recommend for any home.

Good stuff

RSS

Photos

Loading…
  • Add Photos
  • View All

Latest Activity

Mick Lane is now a member of Home Energy Pros
6 hours ago
Empower Efficiency added 2 discussions to the group Job Board
7 hours ago
Tom White's video was featured

A net-zero builders formula for insulating a super energy efficient home

Here is Peter Amerongen's formula for insulating a super energy efficient home.
12 hours ago
Dale@EnergyWright replied to Don Hynek's discussion Superinsulation retrofit is Complete!
"Very nice! I'd like to do the same with my 1885 home. Can you tell us more about foundation…"
yesterday
Colin Genge updated an event
Thumbnail

Measuring HVAC Performance webinar at Online

February 23, 2016 from 11am to 12pm
Learning Objectives:How to measure HVAC total flow.Use your gauge for static pressure and remote…See More
yesterday
Colin Genge updated an event
Thumbnail

Testing for IECC Code Compliance for duct and house leakage webinar at Online

February 16, 2016 from 11am to 12pm
Learning Objectives:Learn the testing options for code compliance.Set up your gauge to get the…See More
yesterday
Colin Genge updated an event
Thumbnail

Tools and Tips for Home Performance Contractors - Learn from the Pros webinar at Online

February 11, 2016 from 11am to 12pm
This webinar is an absolute must if you are or want to be a Home Performance contractor.Learn what…See More
yesterday
Profile IconSarah Ralich, Sam Taylors and Greg Winks joined Home Energy Pros
yesterday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service