Surface effective leakage area

asked 9 years ago

Jevin
197 ●7

updated 9 years ago

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

Greetings to everybody.

I am modelling a free flowing residential house through an airflow network for i intend to use some passive strategies for induced ventilation in the house for my thesis.

From what i gathered infiltration in the Airflow network is modeled either through surface cracks or surface effective leakage area.

Is there any literature on the difference between the 2 ? Is there a set of lookup values (tables ) for concrete walls ?

How about the reference crack conditions ? what are the values that should be used. I have no access to the house for physical measurements.

Thank you for your help

answered 9 years ago

Jason DeGraw

2208 ●6 ●10 https://github.com/jasondegraw

The is a lot of literature on this, for EnergyPlus the best places to start are

the EnergyPlus documentation here, both the engineering reference and the I/O reference
the ASHRAE Handbook of Fundamentals "Ventilation and Infiltration" chapter, older versions (2001 and earlier) included a table of effective leakage areas for residential applications.

You might also check COMIS Fundamentals (LBL-28560) here or CONTAM's documentation (NIST-TN-1887) here. The EnergyPlus pressure network implementation is similar to what is in COMIS and CONTAM, so it may provide some context.

As for what reference conditions to use, for effective leakage area you can convert from one set to another as long as you are careful. The role that the conditions play is described in the ASHRAE Handbook of Fundamentals chapter, see equation 41 and the surrounding discussion (in the 2013 edition). The exact values are probably less important than making sure that the overall airtightness of your model is representative of the type of building that you are modeling. There is residential data on that in the Handbook of Fundamentals chapter and a database of residential airtightness maintained by Berkeley Lab here.

link

Comments

Thank you very much for the answer Sir. I started looking into the reference material and i think I shall find the info required there. Thanks again for the help.