Thermal Performance of PNIPAm as an Evaporative Cooling Medium within a Ventilated Wall Cavity

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Description
Learning from the anatomy of leaves, a new approach to bio-inspired passive evaporative cooling is presented that utilizes the temperature-responsive properties of PNIPAm hydrogels. Specifically, an experimental evaporation rate from the polymer, PNIPAm, is determined within an environmental chamber, which

Learning from the anatomy of leaves, a new approach to bio-inspired passive evaporative cooling is presented that utilizes the temperature-responsive properties of PNIPAm hydrogels. Specifically, an experimental evaporation rate from the polymer, PNIPAm, is determined within an environmental chamber, which is programmed to simulate temperature and humidity conditions common in Phoenix, Arizona in the summer. This evaporation rate is then used to determine the theoretical heat transfer through a layer of PNIPAm that is attached to an exterior wall of a building within a ventilated cavity in Phoenix. The evaporation of water to the air gap from the polymer layer absorbs heat that could otherwise be conducted to the interior space of the building and then dispels it as a vapor away from the building. The results indicate that the addition of the PNIPAm layer removes all heat radiated from the exterior cladding, indicating that it could significantly reduce the demand for air conditioning at the interior side of the wall to which it is attached.
Date Created
2018
Agent

Operational and technological peak load shifting strategies for residential buildings

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Description
Residential air conditioning systems represent a critical load for many electric

utilities, especially for those who serve customers in hot climates. In hot and dry

climates, in particular, the cooling load is usually relatively low during night hours and

early mornings and hits

Residential air conditioning systems represent a critical load for many electric

utilities, especially for those who serve customers in hot climates. In hot and dry

climates, in particular, the cooling load is usually relatively low during night hours and

early mornings and hits its maximum in the late afternoon. If electric loads could be

shifted from peak hours (e.g., late afternoon) to off-peak hours (e.g., late morning), not

only would building operation costs decrease, the need to run peaker plants, which

typically use more fossil fuels than non-peaker plants, would also decrease. Thus, shifting

electricity consumption from peak to off-peak hours promotes economic and

environmental savings. Operational and technological strategies can reduce the load

during peak hours by shifting cooling operation from on-peak hours to off-peak hours.

Although operational peak load shifting strategies such as precooling may require

mechanical cooling (e.g., in climates like Phoenix, Arizona), this cooling is less

expensive than on-peak cooling due to demand charges or time-based price plans.

Precooling is an operational shift, rather than a technological one, and is thus widely

accessible to utilities’ customer base. This dissertation compares the effects of different

precooling strategies in a Phoenix-based utility’s residential customer market and

assesses the impact of technological enhancements (e.g., energy efficiency measures and

solar photovoltaic system) on the performance of precooling. This dissertation focuses on

the operational and technological peak load shifting strategies that are feasible for

residential buildings and discusses the advantages of each in terms of peak energy

savings and residential electricity cost savings.
Date Created
2016
Agent

Obtaining LEED credits directed towards healthy inpatient block

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Description
ABSTRACT Leadership in Energy and Environmental Design (LEED) is a non-governmental organization of U.S. Green Building Council (USGBC) which promotes a sustainable built environment with its rating systems. One of the building segments which it considers is healthcare, where it

ABSTRACT Leadership in Energy and Environmental Design (LEED) is a non-governmental organization of U.S. Green Building Council (USGBC) which promotes a sustainable built environment with its rating systems. One of the building segments which it considers is healthcare, where it is a challenge to identify the most cost-effective variety of complex equipments, to meet the demand for 24/7 health care and diagnosis, and implement various energy efficient strategies in inpatient hospitals. According to their “End Use Monitoring” study, Hospital Energy Alliances (HEA), an initiative of U.S. Department of Energy (DOE), reducing plug load reduces hospital energy consumption. The aim of this thesis is to investigate the extent to which realistic changes to the building envelope, together with HVAC and operation schedules would allow LEED credits to be earned in the DOE–hospital prototype. The scope of this research is to specifically investigate the inpatient block where patient stays longer. However, to obtain LEED credits the percentage cost saving should be considered along with the end use monitoring. Several steps have been taken to identify the optimal set of the end use results by adopting the Whole Building Energy Simulation option of the LEED Energy & Atmosphere (EA) pre– requisite 2: Minimum Energy Performance. The initial step includes evaluating certain LEED criteria consistent with ASHRAE Standard 90.1–2007 with the constraint that hospital prototype is to be upgraded from Standard 2004 to Standard 2007. The simulation method stipulates energy conservation measures as well as utility costing to enhance the LEED credits. A series of simulations with different values of Light Power Density, Sizing Factors, Chiller Coefficient of Performance, Boiler Efficiency, Plug Loads and utility cost were run for a variety of end uses with the extreme climatic condition of Phoenix. These assessments are then compared and used as a framework for a proposed interactive design decision approach. As a result, a total of 19.4% energy savings and 20% utility cost savings were achieved by the building simulation tool, which refer to 5 and 7 LEED credits respectively. The study develops a proper framework for future evaluations intended to achieve more LEED points.
Date Created
2012
Agent