초록

Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

대표청구항 ▼

1. A method for inhibiting corrosion of steel in an ammonia/water heat pump, comprising: cerating steel surfaces that will be exposed to an ammonia/water working fluid; and introducing a rare earth metal salt to an ammonia/water working fluid in a heat pump having steel surfaces exposed to the w

1. A method for inhibiting corrosion of steel in an ammonia/water heat pump, comprising: cerating steel surfaces that will be exposed to an ammonia/water working fluid; and introducing a rare earth metal salt to an ammonia/water working fluid in a heat pump having steel surfaces exposed to the working fluid, wherein the rare earth metal includes yttrium. 2. The method of claim 1, wherein the rare earth metal salt includes cerium. 3. The method of claim 1, wherein the rare earth metal comprises cerous nitrate. 4. The method of claim 3, wherein the concentration of rare earth metal salt in the ammonia/water working fluid is between about 5 mM and about 350 mM. 5. The method of claim 1, wherein the rare earth metal salt includes cerium sulfate. 6. The method of claim 5, wherein the concentration of rare earth metal salt in the ammonia/water working fluid is between about 5 mM and about 350 mm. 7. The method of claim 1, wherein the rare earth metal salt includes yttrium sulfate. 8. The method of claim 7, wherein the concentration of rare earth metal salt in the ammonia/water working fluid is between about 5 mM and about 350 mM. 9. The method of claim 1, wherein the steel surfaces are cerated by exposing the steel surfaces to a cerium chloride solution including about 1 to 2.5 weight-percent hydrogen peroxide at about room temperature for about 20 minutes. 10. The method of claim 9, wherein the solution includes lead acetate and a wetting agent. 11. The method of claim 9, further comprising the step of sealing the cerated surfaces by exposing the surfaces to a silicate solution at about 50° C. for about 30 minutes. 12. The method of claim 11, wherein the silicate solution is about 10% sodium meta-silicate. 13. The method of claim 1, further comprising the step of sealing cracks in the cerated surface by immersing the cerated seal in a boiling REMS solution. 14. The method of claim 13, wherein the boiling REMS solution is a cerous nitrate solution. 15. The method of claim 14, wherein the boiling REMS solution is a cerium nitrate solution. 16. The method of claim 14, wherein the boiling REMS solution is a cerium sulfate solution. 17. The method of claim 13, wherein the boiling REMS solution also contains ammonia. 18. The method of claim 13, wherein the boiling REMS solution is a yttrium salt solution. 19. The method of claim 18, wherein the boiling REMS solution is a yttrium sulfate solution. 20. A method of inhibiting both corrosion of steel surfaces and dissociation of ammonia in a heat pump having an ammonia/water working fluid comprising: insulating the steel surfaces with a cerated layer; and introducing a rare earth metal salt to the working fluid. 21. A corrosion-resistant heat pump comprising: a steel housing wherein the steel housing is coated with a yttrium compound; and an ammonia/water working fluid contained in the steel housing, the ammonia water/working fluid including a rare earth metal salt, wherein the rare earth metal salt includes yttrium. 22. The corrosion-resistant heat pump of claim 21, wherein the rare earth metal salt includes cerium. 23. The corrosion-resistant heat pump of claim 22, wherein the steel housing is coated with a cerium compound. 24. The corrosion-resistant heat pump of claim 22, wherein the concentration of rare earth metal salt in the ammonia/water working fluid is between about 5 mM and about 350 mM. 25. The corrosion-resistant heat pump of claim 21, wherein the concentration of rare earth metal salt in the ammonia/water working fluid is between about 5 mM and about 350 mM.