Hello Micaela
Below are the calculations very helpfully worked out for me by Lactnetter Veronica Garea.
As you can see, a considerable amount of fuel is required to formula feed.
Karleen Gribble
Australia

Energy required to heat 24L of water from 15oC to boiling temperature at sea level, that is 100oC, is given by the equation Q=m cp (100-15)K (where Q is the amount of energy required, m is the mass of water, cp is the heat capacity of water, that is cp=4.817 kJ/(kg K) and the numbers in parenthesis represents the temperature difference). Then, Q= 23.5 kg x 4.817 kJ/(kg K) x 85 K = 9621.96 kJ per day of energy required. LPG has a specific caloric value of 46.1MJ/kg. However, this energy cannot be perfectly used to heat water, it is estimated that 90% of the energy will be lost. Thus the estimate of the amount of LPG per day required is 2kg per day or 14kg for one week.

-----Original Message-----
From: Lactation Information and Discussion [mailto:[log in to unmask]] On Behalf Of M N
Sent: Friday, 18 February 2011 7:54 AM
To: [log in to unmask]
Subject: Re: any physicists on Lactnet?

Well, I am intrigued...

Following my husband's suggestions, I think the simplest way to
address the problem is that you evaluate the number of minutes of
burning that the entire process you describe needs to be completed
using some standard (kitchen?) burner.
I can give you the gas needed to use that burner at maximum power for
one minute.

             ***********************************************

Archives: http://community.lsoft.com/archives/LACTNET.html
To reach list owners: [log in to unmask]
Mail all list management commands to: [log in to unmask]
COMMANDS:
1. To temporarily stop your subscription write in the body of an email: set lactnet nomail
2. To start it again: set lactnet mail
3. To unsubscribe: unsubscribe lactnet
4. To get a comprehensive list of rules and directions: get lactnet welcome