Economics of Residential Heat Recovery Units

Determining residential airconditioning waste heat recovery system costs and savings is achieved using a computer program. A worksheet is designed to accept consumer data as an input to the program. The program features load and waste heat recovery calculations on a monthly basis. Economic criteria, including rate of return, present worth, and payback period are computed. Sensitivity of these criteria to fuel escalation and consumer discount rate is demonstrated. the program provides the user with both thermal analysis and economic analysis summary reports

Picosecond Laser based Additive Manufacturing of Hydroxyapatite Coatings on Cobalt Chromium Surfaces

We report high repetition rate picosecond laser based additive manufacturing process to coat nanoscale rough hydroxyapatite (HA) on cobalt chromium plates (CoCr). Nanoscale rough coatings of hydroxyapatite are desirable as they mimic the naturally formed hydroxyapatite and in addition provide very high surface area and surface roughness, which leads to better cell adhesion and cell-matrix interaction. Nanoscale HA powders are synthesized using sol-gel procedure and ball milling. Ball-milled powders are suspended in volatile solvents and coated on the CoCr surface using picosecond laser irradiation. The chemical composition and morphology of the coated material was characterized using electron microscopy. The laser-assisted fusion process results in HA coatings that have hierarchical surface roughness down to nanometer scale which may enhance the biocompatibility of the CoCr implants