The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform
William J. Fisk - One of the best experts on this subject based on the ideXlab platform.
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Energy and IAQ Implications of Alternative Minimum Ventilation Rates in California Retail and School Buildings
2015Co-Authors: Spencer Dutton, William J. FiskAbstract:For a stand-alone retail building, a primary school, and a secondary school in each of the 16 California climate zones, the EnergyPlus building energy simulation model was used to estimate how minimum mechanical ventilation rates (VRs) affect energy use and indoor air concentrations of an indoor-Generated Contaminant. The modeling indicates large changes in heating energy use, but only moderate changes in total building energy use, as minimum VRs in the retail building are changed. For example, predicted state-wide heating energy consumption in the retail building decreases by more than 50% and total building energy consumption decreases by approximately 10% as the minimum VR decreases from the Title 24 requirement to no mechanical ventilation. The primary and secondary schools have notably higher internal heat gains than in the retail building models, resulting in significantly reduced demand for heating. The school heating energy use was correspondingly less sensitive to changes in the minimum VR. The modeling indicates that minimum VRs influence HVAC energy and total energy use in schools by only a few percent. For both the retail building and the school buildings, minimum VRs substantially affected the predicted annual-average indoor concentrations of an indoor Generated Contaminant, with larger effects in schools.more » The shape of the curves relating Contaminant concentrations with VRs illustrate the importance of avoiding particularly low VRs.« less
Alexey V. Gorshkov - One of the best experts on this subject based on the ideXlab platform.
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Dissipation induced dipole blockade and anti-blockade in driven Rydberg systems
Physical Review A, 2018Co-Authors: Jeremy Young, T. Boulier, Eric Magnan, Elizabeth A. Goldschmidt, Ryan Wilson, Steven L. Rolston, James V. Porto, Alexey V. GorshkovAbstract:We study theoretically and experimentally the competing blockade and anti-blockade effects induced by spontaneously Generated Contaminant Rydberg atoms in driven Rydberg systems. These Contaminant atoms provide a source of strong dipole-dipole interactions and play a crucial role in the system's behavior. We study this problem theoretically using two different approaches. The first is a cumulant expansion approximation, in which we ignore third-order and higher connected correlations. Using this approach for the case of resonant drive, a many-body blockade radius picture arises, and we find qualitative agreement with previous experimental results. We further predict that as the atomic density is increased, the Rydberg population's dependence on Rabi frequency will transition from quadratic to linear dependence at lower Rabi frequencies. We study this behavior experimentally by observing this crossover at two different atomic densities. We confirm that the larger density system has a smaller crossover Rabi frequency than the smaller density system. The second theoretical approach is a set of phenomenological inhomogeneous rate equations. We compare the results of our rate equation model to the experimental observations in [E. A. Goldschmidt, et al., PRL 116, 113001 (2016)] and find that these rate equations provide quantitatively good scaling behavior of the steady-state Rydberg population for both resonant and off-resonant drive.
Spencer Dutton - One of the best experts on this subject based on the ideXlab platform.
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Energy and IAQ Implications of Alternative Minimum Ventilation Rates in California Retail and School Buildings
2015Co-Authors: Spencer Dutton, William J. FiskAbstract:For a stand-alone retail building, a primary school, and a secondary school in each of the 16 California climate zones, the EnergyPlus building energy simulation model was used to estimate how minimum mechanical ventilation rates (VRs) affect energy use and indoor air concentrations of an indoor-Generated Contaminant. The modeling indicates large changes in heating energy use, but only moderate changes in total building energy use, as minimum VRs in the retail building are changed. For example, predicted state-wide heating energy consumption in the retail building decreases by more than 50% and total building energy consumption decreases by approximately 10% as the minimum VR decreases from the Title 24 requirement to no mechanical ventilation. The primary and secondary schools have notably higher internal heat gains than in the retail building models, resulting in significantly reduced demand for heating. The school heating energy use was correspondingly less sensitive to changes in the minimum VR. The modeling indicates that minimum VRs influence HVAC energy and total energy use in schools by only a few percent. For both the retail building and the school buildings, minimum VRs substantially affected the predicted annual-average indoor concentrations of an indoor Generated Contaminant, with larger effects in schools.more » The shape of the curves relating Contaminant concentrations with VRs illustrate the importance of avoiding particularly low VRs.« less
Harmohindar Singh - One of the best experts on this subject based on the ideXlab platform.
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Carbon Dioxide and Ventilation Rates.
1995Co-Authors: Glen A. Chamberlin, Darren B. Myers, James M. Jones, Peter Rojeski, Harmohindar SinghAbstract:Abstract : In many buildings, the occupants themselves are a major Contaminant source. Carbon dioxide (CO2) is one common human-Generated Contaminant. ASHRAE Standard 62-1989 states that the CO2 level in the indoor air should not exceed 1000 parts per million (ppm). The most common method used to remove such Contaminants from indoor air is to bring outdoor air into a building through an air-handling system by mechanical ventilation. However, fresh-air ventilation entails heating or cooling of the outside air to acceptable levels for indoor thermal comfort an energy-expensive process. A system designed to respond to CO2 levels by introducing fresh outdoor air into air-handling systems 'on-demand' may provide the optimal balance between energy efficiency and indoor air quality (IAQ). This study investigated the relationship between ventilation rates and CO2 levels and their interaction in maintaining healthy IAQ, reviewed current gas-sensing technologies, and concluded that further research in the incorporation of gas-sensing technologies into Army Heating, Ventilation, and Air-Conditioning (HVAC) systems is warranted.
Loren C. Zumwalt - One of the best experts on this subject based on the ideXlab platform.
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Role of contamination analysis in resolving concerns relating to the Hubble Space Telescope (HST) open-door deployment at the conclusion of the first servicing mission
Optical System Contamination: Effects Measurements and Control IV, 1994Co-Authors: Steve C. Kwan, Loren C. ZumwaltAbstract:For the Hubble Space Telescope (HST) First Servicing MIssion (FSM) Project there was a high level requirement which stated that the Endeavour would not carry extra propellant for an extra EVA after the final regularly scheduled fifth EVA. Because of this the HST FSM Project needed to assess the feasibility of redeploying the HST with its Aperture Door (AD) open from the Endeavour in order to prevent the situation that the AD may not open by radio command after separation. Contamination was one of the major concerns of the HST scientific community. The prospect that the opened AD may allow unacceptable amount of Endeavour Generated Contaminant to enter the HST aperture and subsequently depositing onto the Primary Mirror seemed too big a risk. To assess this potential contamination threat and to put it into proper perspective, Lockheed performed a series of comprehensive contamination analyses to predict expected Endeavour Generated molecular and particulate Contaminant accretions on the HST primary mirror during open-AD re-deployment. This paper describes the analysis approach and some of the conclusions reached for the HST FSM redeployment phase.