Subject: Re: Help cool my Bunnies

From: [email-masked] (Nick Pine)
Date: 21 May 1996 17:32:18 -0400

Dave Cruikshank <[email-masked]> wrote:

>Hi, I'm just an Homedweller not an HVAC person, but I was 
>hoping to garner some info form the experts.

I have forwarded your message to the August sci.engr.heat-vent-ac group,
a collection of freon pumpers who should now be able to help with your
rabbit problem, owing to some recent educational postings there. 

>My Wife, Child, myself and 9 house rabbits live on the 2&3rd floor
>of a 3 story stick construction home.

I understand your desire to heat your house with rabbits, but you should seek
professional help. Everything is in the system design. Did you have an HVAC
professional estimate the number of rabbits you would need? Perhaps not, if
you are having cooling problems now.  When will people learn? Cows might have
been better, but they are contraindicated on the second floor of a house... 

>We own our own business and have a very tight budget.

You are going in the right direction, with rabbit heat :-) Have you
considered barbecuing the parents this summer, after they have had their
cute little litters? Smaller rabbits make fewer Btu/hr, and they will
grow larger by winter. Your HVAC professional should have suggested a
seasonal breeding and harvest plan.

>We live on the currently very hot & humid Mid-atlantic, PA

What is the nearest town to your hutch? Harrisburg, with an average temp
in July of 75.7 F, and average daily mins and maxes of 65.6 and 85.8?
The freon pumpers will doubtless suggest conventional AC, but you can
do it with thermal mass and insulation, if you ventilate at night and
button the place up during the day. Is a roof pond possible, or a pond
on the north side of the house? 

>Using a whole house fan, and or the two Window AC units we now have,
>what is the best way to keep it under 80.  

Fill your house up with thermal mass. Say you have R13 walls and ceiling,
3,000 ft^2 of them, and an air infiltration rate of 1 ACH and a volume of
16K ft^3, ie an air inf. rate of 266 cfm for a heat loss coefficient of
about 500 Btu/hr-F. You and your bunnies (can you get them to live outside
in the summer?) will make about 6,000 Btu/hour of heat, and the house will
admit about another 8h (86-80) 500 = 24K Btu on an average day, for a daily
cooling load of approximately 170K Btu/day, plus a modest electricity usage
amounting to 70K Btu/day, for a total of 240K Btu/day. To store coolth at
70 F for 5 days at that max temp you need to store 1.2 million Btu in a
thermal mass C such that 10C = 1.2M, ie C = 120K Btu/F. The house walls and
furnishings might have a heat capacity of 3K Btu/F, so you need another 234
55 gallon drums full of water, accent drums, sprinkled around the house.
Or a lot more concrete furniture.

>Is it best to keep an insulated home sealed up.

Yes, during the day.

>Or should we open a 2nd floor window and put a large fan in the attic.

Yes, at night.

>Would it help to put reflective foil and foam insulation in the sunside
>windows to seal them off.  Any suggestions would be greatly appreciated.  

Yes. And it would probably help to shade the south wall with a big black
piece of greenhouse shadecloth, or Dewitt black polypropylene "weed control
cloth" at $78 for a 4' wide x 250' roll at Home Depot. 

Nick