Thermodynamic evaluation of a microscale heat pump

The development of microscale thermal components has reached a level of maturity that suggests that complete microthermal systems can be developed. This paper presents the results of a thermodynamic evaluation of a microscale heat pump for space heating and cooling applications. The concept involves fabricating individual unit processes on separate sheets of material and then combining the sheets to form complete systems. The sheet architecture allows a large number of microheat pumps to be fabricated and operated in parallel. Results of the thermodynamic analysis suggest that the microscale heat pump is theoretically feasible. Pressure drop in the evaporators and condensers was not significant, and performance requirements for the microscale compressor are challenging but not unattainable. Results also suggest that there is significant potential for improving heat pump performance by optimizing the integration of the heat pump with the microchannel evaporators and condensers. Sensitivity studies investigated the impact of working fluid selection, heat exchanger approach temperature, and compressor efficiency on cycle performance. Based on the results of this evaluation, additional research on microscale heat exchangers and compressors is suggested

Aerosol characteristics in the offgas from a pilot-scale sluicing operation

A pilot-scale study was performed to simulate conditions anticipated during sluicing operations to retrieve waste in single-shell Tank 241-C-106 at the US Department of Energy`s Hanford Site in southeastern Washington. The objective of the study was to identify and characterize the potential aerosol source term at the inlet of the headspace exhaust ventilation system during sluicing operations. The information is needed to support decisions for components to be used in the full-scale operation. A secondary objective was to qualitatively evaluate the visibility during sluicing. Three simulated sluicing tests were performed in the 336 Building`s quarter-scale waste tank facility located at Hanford. Scaling relationships were used to guide modifications to the quarter-scale tank to accommodate tests that simulated tank geometry, sluicing, and ventilation conditions in the full-scale tank. Simulated sluicing fluids were targeted on solid and liquid surfaces during the tests. Test conditions were monitored, and aerosol measurements were made in the offgas ventilation duct. Also during the tests, an in-tank camera was used to monitor visibility

Offgas characterization from the radioactive NCAW core sample (102-AZ-C1) and simulant during HWVP feed preparation testing: Letter report

The primary objective of the Radioactive Process/Product Laboratory Testing (RPPLT) is to provide preliminary confirmation that the nonradioactive waste feed stimulant recipe is adequate for addressing the testing needs of design, safety, waste form qualification (WFO), and permitting of the Hanford Waste Vitrification Plant HWVP). The information contained In this letter report specifically addresses offgas production during the formating, digestion, and recycle addition of the third Neutralized Current Acid Waste (NCAW) core sample and core stimulant. Testing was conducted using a laboratory-scale version of the HWVP flowsheet

Recycle Waste Collection Tank (RWCT) simulant testing in the PVTD feed preparation system

(This is part of the radwaste vitrification program at Hanford.) RWCT was to routinely receive final canister decontamination sand blast frit and rinse water, Decontamination Waste Treatment Tank bottoms, and melter off-gas Submerged Bed Scrubber filter cake. In order to address the design needs of the RWCT system to meet performance levels, the PNL Vitrification Technology (PVTD) program used the Feed Preparation Test System (FPTS) to evaluate its equipment and performance for a simulant of RWCT slurry. (FPTS is an adaptation of the Defense Waste Processing Facility feed preparation system and represents the initially proposed Hanford Waste Vitrification Plant feed preparation system designed by Fluor-Daniel, Inc.) The following were determined: mixing performance, pump priming, pump performance, simulant flow characterization, evaporator and condenser performance, and ammonia dispersion. The RWCT test had two runs, one with and one without tank baffles