A simple calculation shows the interesting result, that the cooling capacity in the ice storage is at similar level as in a lead battery based on both volume and weight.

One supplier of lead battery informs, that a 50 Ah, 12 Volts battery has the weight of 13,6 kg. The dimesions are 0.24*0.175*0.175 meters. The energy content of 50 Ah can be calculated as a specific energy content of 0.159 MJ/kg or 294 MJ/m3.

The cooling system will have a COP-value (coefficient of performance) of about 1.3 (Danfoss BD35F, CECOMAF-data for -15 °С, 2000 RPM). This will result in a specific cooling capacity of 0.206 MJ/kg or 382 MJ/m3. For the ice storage: the specific cooling capacity is identical to the melting heat of ice, which is 0.333 MJ/kg or 333 MJ/m3.

The conclusion is, that the specific cooling capacity of ice is 62 % higher compared to lead battery on basis of weight and 13 % smaller compared with lead battery based on volume. In reality, the ice storage outperforms the lead-acid battery, because the allowed daily cycling is less than the nominal 50 Ah, which corresponds to 100% depth of discharge.