Inverse latent heat thermal energy storage system, method for capturing and releasing latent heat
The invention provides a method for storing and releasing heat having the steps of thermally contacting thermal transfer fluid to a mixture of foam and phase change material for a time sufficient for the material to change from a first phase to a second phase during a time when electricity rates are at a first price point; maintaining said material in the second phase until electricity rates are at a second point, wherein the second point is higher than the first price point; and thermally contacting the thermal transfer fluid to the composite in the second phase for a time sufficient for the material to change from the second phase to the first phase. The invention also provides an energy storage module having a mixture of phase change material and high surface area substrate
1. A method for storing and releasing heat comprising:
a. confining thermal transfer fluid to a loop;
b. thermally contacting the thermal transfer-fluid- to a mixture of thermally conductive foam and phase change material for a time sufficient for the material to change from a first phase to a second phase during a time when electricity rates are at a first price point, such that the mixture is stored at about 32 degrees F.;
c. maintaining said material in the second phase until electricity rates are at a second price point, wherein the second price point is higher than the first price point; and
d. thermally contacting the thermal transfer-fluid to the material in the second phase for a time sufficient for the material to change back from the second phase to the first phase.
2. The method as recited in claim 1 wherein the phase change material is homogeneously mixed with the foam having a porosity of between about 80 percent and 90 percent.
3. The method as recited in claim 1 wherein the mixture comprises about 80 percent to about 90 percent by volume of phase change material.
4. The method as recited in claim 1 wherein the mixture exhibits a latent heat of fusion of about 100 to 400 kJ/kg.
5. The method as recited in claim 1 wherein the system is installed in a building with an existing air conditioner and the system is used first for air conditioning and the air-conditioner is used second for air conditioning.
6. The method as recited in claim 1 wherein the system is installed in a building with an existing air conditioner and the existing air conditioner is only run when electric rates are lowest.
7. The method as recited in claim 6 wherein the air conditioner charges the system.
8. The method as recited in claim 1 wherein the system is installed in a building with an existing air conditioner which is run simultaneously with the system.
9. The method as recited in claim 1 wherein the fluid is in fluid communication with a compressor and the mixture.
10. The method as recited in claim 1 wherein the fluid is a refrigerant.
11. The method as recited in claim 1 wherein the loop is encapsulated by the mixture.