Laboratory Evaluation of Energy Recovery Ventilators

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Preconditioning Outside Air: Cooling Loads from Building Ventilation

HVAC equipment manufacturers, specifiers and end users interacting in the marketplace today are only beginning to address the series of issues promulgated by the increased outside air requirements in ASHRAE Standard 62- 1989, "Ventilation for Acceptable Indoor Air Quality", that has cascaded into building codes over the early to mid 1990's. There has been a twofold to fourfold increase in outside air requirements for many commercial building applications, compared to the 1981 version of the standard. To mitigate or nullify these additional weather loads, outdoor air preconditioning technologies are being promoted in combination with conventional HVAC operations downstream as a means to deliver the required fresh air and control humidity indoors. Preconditioning is the term applied for taking outside air to the indoor air setpoint (dry bulb temperature and relative humidity). The large humidity loads from outside air can now be readily recognized and quantified at cooling design point conditions using the extreme humidity ratios/dew points presented in the ASHRAE Handbook of Fundamentals Chapter 26 "Climatic Design Information". This paper presents an annual index called the Ventilation Load Index (VLI), recently developed by the Gas Research Institute (GRI) that measures the magnitude of latent (and sensible) loads for preconditioning outside air to indoor space conditions over the come of an entire year. The VLI has units of ton-hrs/scfm of outside air. The loads are generated using new weather data binning software called ~BinMaker, also from GRI, that organizes the 239 city, 8760 hour by hour, TMY2 weather data into user selected bidtables. The VLI provides a simple methodology for accessing the cooling load impact of increased ventilation air volumes and a potential basis for defining a "humid" climate location

Bubbly cavitating flow generation and investigation of its erosional nature for biomedical applications

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.The paper presents a study of the generation of hydrodynamic bubbly cavitation in microchannels to investigate the destructive energy output resulting from this phenomenon and its potential use in biomedical applications. The research performed in this study includes the experimental results from bubbly cavitation experiments and the findings showing the destructive effects of bubbly cavitating flow on selected specimens and cells. The bubbles caused by hydrodynamic cavitation are highly destructive at the surfaces of the target medium on which they are carefully focused. The resulting destructive energy output could be effectively used for good means such as destroying kidney stones or killing infected cancer cells. Motivated by this potential, the cavitation damage (material removal) to cancerous cells and chalk pieces having similar material properties as calcium phosphate in human bones was investigated. Also the potential of hydrodynamic bubbly cavitation generated at the microscale for biomedical treatments was revealed using the microchannel configuration of a microorifice (with an inner diameter of 0.147 mm and a length of 1.52cm).This work was supported by Sabancı University Internal Grant for Research Program under Grant FRG-C47004

Experimental investigation of non-uniform heating effect on flow boiling instabilities in a microchannel-based heat sink

Copyright @ 2011 ElsevierTwo-phase flow boiling in microchannels is one of the most promising cooling technologies for coping with high heat fluxes produced by the next generation of central processor units (CPUs). If flow boiling is to be used as a thermal management method for high heat flux electronics it is necessary to understand the behaviour of a non-uniform heat distribution, which is typically the case observed in a real operating CPU. The work presented is an experimental study of two-phase boiling in a multi-channel silicon heat sink with non-uniform heating, using water as the cooling liquid. Thin nickel film sensors, integrated on the back side of the heat sinks were used in order to gain insight related to temperature fluctuations caused by two-phase flow instabilities under non-uniform heating. The effect of various hotspot locations on the temperature profile and pressure drop has been investigated. It was observed that boiling inside microchannels with axially non-uniform heating leads to high temperature non-uniformity in the transverse direction.This research was supported by the UK Engineering and Physical Sciences Research Council through grant EP/D500109/1

Emerging, Cost-Effective Applications for Desiccant Dehumidification in the U.S.

Gas-fired desiccant dehumidification systems are now being specified for many supermarkets, ice arenas and cold warehouses, with installations now numbering in the thousands. Their cost effectiveness is due to the economic benefits of improved refrigeration operations resulting from the introduction of drier air. New application niches in the commercial sector are emerging due to the increased outside air quantities required by Indoor Air Quality codes and standards such as ASHRAE Standard 62- 1989. In this paper, a competitive economic analysis of desiccant and other HVAC equipment, generated using a new desiccant screening tool driven by DOE-2.1E simulations, will be presented for several representative buildings in selected U.S. citie

Water Splitting Photovoltaic-Photoelectrochemical GaAs/InGaAsP - WO3/BiVO4 Tandem Cell with Extremely Thin Absorber Photoanode Structure

We demonstrate highly efficient solar hydrogen generation via water splitting by photovoltaicphotoelectrochemical (PV-PEC) tandem device based on GaAs/InGaAsP (PV cell) and WO3/BiVO4 core/shell nanorods (PEC cell). We utilized extremely thin absorber (ETA) concept to design the WO3/BiVO4 core/shell heterojunction nanorods and obtained the highest efficiencies of photo-induced charge carriers generation, separation and transfer that are possible for the WO3/BiVO4 material combination. The PV-PEC tandem shows stable water splitting photocurrent of 6.56 mA cm-2 under standard AM1.5G solar light that corresponds to the record solar-to-hydrogen (STH) conversion efficiency of 8.1%

Creating a Gold Medal Olympic and Paralympics Health Care Team: A Satisfaction Survey of the Mobile Medical Unit/Polyclinic Team Training for the Vancouver 2010 Winter Games

BACKGROUND: The mobile medical unit/polyclinic (MMU/PC) was an essential part of the medical services to support ill or injured Olympic or Paralympics family during the 2010 Olympic and Paralympics winter games. The objective of this study was to survey the satisfaction of the clinical staff that completed the training programs prior to deployment to the MMU. METHODS: Medical personnel who participated in at least one of the four training programs, including (1) week-end sessions; (2) web-based modules; (3) just-in-time training; and (4) daily simulation exercises were invited to participate in a web-based survey and comment on their level of satisfaction with training program. RESULTS: A total of 64 (out of 94 who were invited) physicians, nurses and respiratory therapists completed the survey. All participants reported favorably that the MMU/PC training positively impacted their knowledge, skills and team functions while deployed at the MMU/PC during the 2010 Olympic Games. However, components of the training program were valued differently depending on clinical job title, years of experience, and prior experience in large scale events. Respondents with little or no experience working in large scale events (45%) rated daily simulations as the most valuable component of the training program for strengthening competencies and knowledge in clinical skills for working in large scale events. CONCLUSION: The multi-phase MMU/PC training was found to be beneficial for preparing the medical team for the 2010 Winter Games. In particular this survey demonstrates the effectiveness of simulation training programs on teamwork competencies in ad hoc groups