The cooling produced by melting of 1 ton of ice in a day is
taken as unit of refrigeration (in tons). Now unit of
refrigeration used in S.I. System is KW.
1 ton of refrigeration
= mass of ice x latent heat of ice / 24 hrs

= 900 kg x 335 KJ/Kg ( one short ton = 900 kgs )
------------------
24 x 3600 secs
= 3.4895 KJ/Sec
say 3.5 KJ / Sec = 3.5 KW

In simple 1 tonne refregeration effect of AC is equal to
same amount of cooling which have been achieved by 1 Tonne
of ice block in 1 hour. i.e 3000K.CAL /HR

One Ton of Refrigeration is cooling capacity of a machine
that can freeze one short ton of water at 0 degree celcius
to ice at 0 degree celcius in 24 hrs.

1 tonne AC : it is the capacity of the unit, which can
remove the heat generated in the particular room ,such that
the amount of heat is equivalent to melt the 1 block of ice
(which is weighing 1 tonne).

One Township having 850 house and each house load is 2.2KW
single phase & 5HP 3 Phase motors of 10 Nos .Who can
calculate 11 KV transformer
capacity .dilip_bhasker@yahoo.co.in