Consider a closed, isolated system that consists of two substances 1 and 2 that both have constant volume and have constant volume heat capacities over the relevant temperature range: Cv1 = 1J/K and...

How is this process accomplished with a refrigerator? I.e., what is needed in order to transfer energy from substance 1 to substance 2, without reducing the total entropy of the closed, isolated system?

Extracted text: Consider a closed, isolated system that consists of two substances 1 and 2 that both have constant volume and have constant volume heat capacities over the relevant temperature range: Cv1 = 1J/K and Cy2 = 2J/K. Substance 1 is initially prepared at T1,0 100K, while substance 2 is initially prepared at T2,0 200K. Suppose instead that we want to cool substance 1 from T, . 100K to Tf = 90K.