Search results for "refrigerator"
showing 10 items of 18 documents
Energy performance evaluation of a demo solar desiccant cooling system with heat recovery for the regeneration of the adsorption material
2012
Abstract Since July 2008, a Solar Desiccant Evaporative Cooling (DEC) system has been operating as a test plant at the solar laboratory of the Dipartimento di Energia (ex DREAM) of the University of Palermo. The system is composed of an air handling unit (AHU) designed for ventilation of the laboratory coupled with a radiant ceiling that provides most of the required sensible cooling/heating energy. Flat plate collectors deliver part of the regeneration heat of the desiccant wheel during the summertime and are used for space heating during the wintertime. The system was designed for high humidity loads because of the typical climate conditions at the site and the need to support a radiant c…
A Validation Methodology for a Combined Heating Cooling and Power (CHCP) Pilot Plant
2004
A great number of variables significantly influence the energetic, environmental and economic results of CHP (Combined Heating and Power) and CHCP (Combined Heating Cooling and Power) plants operation, and as a consequence their project activity is rather complex. In order to select the best layout and properly size the machines, detailed data on hourly electric, thermal, and cooling demand are necessary, so that a series of plant life cycle simulations may have to be carried out. Unfortunately, such detailed data are rarely available, because energy consumptions data for existing buildings are usually derived from aggregated monthly or bimonthly gas and electricity bills. Even more difficu…
Pumped helium system for cooling positron and electron traps to 1.2 K
2011
Abstract Extremely precise tests of fundamental particle symmetries should be possible via laser spectroscopy of trapped antihydrogen ( H ¯ ) atoms. H ¯ atoms that can be trapped must have an energy in temperature units that is below 0.5 K—the energy depth of the deepest magnetic traps that can currently be constructed with high currents and superconducting technology. The number of atoms in a Boltzmann distribution with energies lower than this trap depth depends sharply upon the temperature of the thermal distribution. For example, ten times more atoms with energies low enough to be trapped are in a thermal distribution at a temperature of 1.2 K than for a temperature of 4.2 K. To date, H…
Absorption equipment for energy savings: A case study in Sicily
2013
Abstract This paper considers a feasibility study on the recovery of the reject heat available from an electric utility with two units operating with 120-MW gas turbines; these units have a heat recovery system that feeds the district heating pipeline of an industrial consortium. Thus, feeding the expeller of the absorption equipment installed in a cooling plant for foodstuff stocking represents an opportunity for the feasibility study. This plant operates at both 0 °C and −18 °C. The feasibility study covers two aspects: (1) the technical feasibility of a suitable absorption cooling plant that uses two separate pieces of absorption equipment working with the pair ammonia–water and (2) the …
A measurement methodology for monitoring a CHCP pilot plant for an office building
2003
Abstract In Mediterranean areas, climate conditions determine quite equal demand both for thermal and cooling energy. The possibility to convert a cooling demand in thermal one through an absorption chiller allows to extend widely the number of running hours of a cogeneration plant. A trigeneration pilot plant for two office building is described, in which an integrated lay-out includes a NG prime mover with heat exchanger, an absorption chiller and a reversible heat pump. The pilot plant is completed and pre-running test were performed. Different fluid dynamics parameters will be monitored, in order to build the actual cumulative curve for thermal power. The measurement methodology is also…
Trigeneration and Polygeneration Configurations for Desalination and Other Beneficial Processes
2018
Abstract The integration of renewable energy sources (geothermal, biomass, and solar) and desalination systems into novel polygeneration plants is investigated. Two main arrangements are considered: geothermal (GP) and biomass (BP) polygeneration. Both systems include concentrating photovoltaic/thermal solar collectors, a multieffect distillation system for seawater desalination, a single-effect LiBr-H2O absorption chiller, storage tanks, heat exchangers, balance-of-plant devices; a biomass auxiliary heater and geothermal wells are also included, in BP and GP, respectively. The systems can provide electricity and hot water, used for space heating, cooling, domestic hot water production, and…
Thermodynamics of a Phase-Driven Proximity Josephson Junction
2019
We study the thermodynamic properties of a superconductor/normal metal/superconductor Josephson junction {in the short limit}. Owing to the proximity effect, such a junction constitutes a thermodynamic system where {phase difference}, supercurrent, temperature and entropy are thermodynamical variables connected by equations of state. These allow conceiving quasi-static processes that we characterize in terms of heat and work exchanged. Finally, we combine such processes to construct a Josephson-based Otto and Stirling cycles. We study the related performance in both engine and refrigerator operating mode.
Helium gas pressure cell for pressures up to 1 kbar (0.1 GPa) in conjunction with the cold head of a closed-cycle He refrigerator
1997
A helium gas pressure cell for pressures up to 1 kbar (0.1 GPa) has been developed in conjunction with a closed-cycle He refrigerator allowing variable temperatures between 15 and 300 K. Both cell and refrigerator are equipped with optical windows suitable for photophysical measurements, such as temperature- and pressure-dependent absorption spectroscopy or laser flash photolysis. Examples of measurements on iron(II) spin-crossover systems are given. In these compounds, comparatively small external pressures induce significant changes in the thermodynamic equilibrium as well as in the relaxation dynamics.
A high power liquid hydrogen target for the Mainz A4 parity violation experiment
2005
We present a new powerful liquid hydrogen target developed for the precise study of parity violating electron scattering on hydrogen and deuterium. This target has been designed to have minimal target density fluctuations under the heat load of a 20$\mu$A CW 854.3 MeV electron beam without rastering the electron beam. The target cell has a wide aperture for scattered electrons and is axially symmetric around the beam axis. The construction is optimized to intensify heat exchange by a transverse turbulent mixing in the hydrogen stream, which is directed along the electron beam. The target is constructed as a closed loop circulating system cooled by a helium refrigerator. It is operated by a …
A new frozen-spin target for 4π particle detection
1999
Abstract A new frozen-spin target has been developed, that allows the detection of emitted particles in an angular acceptance of almost 4π in the laboratory frame. The central part of this new target represents a 3He/4He dilution refrigerator that is installed horizontally along the beam axis. The refrigerator includes an internal superconducting holding coil to maintain the nucleon polarization in the frozen-spin mode longitudinally to the beam. The design of the dilution refrigerator and the use of an internal holding coil enabled for the first time the measurement of a spin-dependent total cross section in combination with a polarized solid state target. This new frozen-spin target was u…