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Dehumidifiers (DHUs) are the second most-selected equipment, after air conditioning (AC), used to manage indoor relative humidity (RH) in homes. They can offer the lowest first-cost, are well-established in the market, and are often easier to install than other supplemental dehumidification alternatives. However, DHUs have the potential to use significant amounts energy and may impact the performance of the central ducted cooling system under certain conditions. Dehumidifiers may be designed to be ducted or un-ducted. Dehumidifiers with ducts are sometimes referred to as whole-house or ducted dehumidifiers. Manufacturer manuals offer several different options for ducting DHUs, but they do not provide adequate information about potential performance impacts. Also sorely missing are expanded DHU performance metrics to help professionals and consumers determine the appropriate DHU capacity and to help predict operational efficiency for specific realistic applications. The Florida Building Commission initiated a research project to determine if some common ducted DHU configurations had significant energy and moisture impacts and whether any configurations should be not allowed in Florida Building Code. The research evaluated measured energy use and latent heat removal rates of AC and DHU for four different common ducted DHU duct configurations. Testing occurred during variable weather and interior latent loads common in a warm moist climate. A highly-instrumented building lab was used to evaluate AC and DHU performance based upon how a DHU was ducted to a central AC ductwork and compared these to a DHU ducted to and from an open central room. There was less than 1% difference in annual space conditioning energy (DHU + AC) among two different methods of DHU ducted to the central supply duct and the DHU ducted directly to indoors. However, steady-state and longer-term test findings showed that a DHU ducted to and from a central cooling system return upstream of the central cooling evaporator coil resulted in the annual predicted space conditioning energy use of 308 kWh/year (4%) more than the DHU ducted directly to indoors. It also resulted in decreased central AC latent performance by 28% when the DHU and AC ran simultaneously. This DHU duct configuration further degraded dehumidification performance by causing moisture to be evaporated off of the central cooling coil at a rate as high as 2-3 pounds of water per hour when the AC was cycled off and DHU operated. This paper discusses the experimental method, results and recommended practice of ducting DHU for optimum performance. [ABSTRACT FROM AUTHOR]

This paper describes a real life project conducted by the Pacific Northwest National Laboratory (PNNL) and PNC Financial Services Group's design team. This is a demonstration project supported by the U.S. Department of Energy's Commercial Partnerships Program. The goal of this project is to design and construct a net-zero energy bank branch in Fort Lauderdale, Florida. The integrated design involved two steps, 1) achieve 50% better energy performance than comparable baseline building, i.e., ANSI/ASHRAE/IESNA Standard 90.1-2004, using the optimized energy efficiency measures (EEMs), 2) then use renewable to cover the remaining energy loads. The lessons learned from this process will be used in the development of all future PNC Branches in the United States. At the concept design phase, the EnergyPlus models were developed to evaluate the EEMs and optimize the design package in terms of energy savings and cost-effectiveness. Despite a comprehensive EEM package, the total energy reduction was only 27% over the baseline. This result turned the team's attention back to PNNL's metering analysis, which revealed that over 50% of energy consumption in a similar branch was contributed from decorative lighting and plug loads. This metering study also revealed a substantial amount of base load existed during business off-hours. Another set of EEMs were proposed to tackle the newly found sources of energy consumption. Exterior lighting was reduced by using LED fixtures for site lighting, signage and decorative lights, and plug loads were reduced by combining ENERGY STAR equipment with off-hours turn off of major equipment. PNC showed great commitment by actively engaging their IT department. The collaboration efforts made it possible to find a solution to tackle the plug loads and save additional 16,000 kWh of electricity. With these changes, the total building energy consumption dropped to 56% of the baseline building consumption, exceeding the target. This paper presents how metering data was used to calibrate models and apply the calibrated modeling analysis results to guide the design team throughout the project design phases. The case study showed the importance of metering and studying the actual energy end use distribution in a building. It also served as a showcase for what is possible when there is commitment from the client and great rapport between design teams. [ABSTRACT FROM AUTHOR]

Modeling of energy use in existing buildings is required for different applications such as building energy management, establishing baselines, and calculating retrofit savings. A single or multivariate regression model is mostly used as a means of developing these models of energy consumption in buildings. This paper explores the applications of single and multivariate models on estimation of monthly energy consumptions in schools and discusses the several aspects of model improvements. Several regression models ranging from a simple only outdoor dry-bulb temperature to multivariate models are studied to find a comprehensive methodology in estimating energy consumptions in schools located in hot and humid climates. Data on energy consumptions in 225 schools selected from four different counties in central Florida are collected to evaluate the models and provide recommendations for improvements. The results show that by including the school scheduling in the model, the accuracy in the monthly energy consumption prediction is significantly improved comparing to that when using only temperature regression model. [ABSTRACT FROM AUTHOR]

Energy wheels are often used to reduce energy consumption and HVAC equipment capacities in buildings, but the effect of the energy wheel on the indoor comfort conditions has not been studied in detail. The addition of an energy wheel to the HVAC system may improve the indoor air relative humidity and perceived air quality as well as reduce energy consumption. A school building is modeled with the TRNSYS computer program, in four North American cities (Saskatoon, Saskatchewan; Vancouver, British Columbia; Tampa, Florida and Phoenix, Arizona) to see the effect of the energy wheel on the indoor comfort in different outdoor climates. The simulations are performed with an energy wheel and without an energy wheel to determine the effects of the energy wheel on the indoor RH and PAQ. Similar simulations have been performed on an office building and presented in a previous paper. The results from the school will be compared to the office building results. In the school, the energy wheel significantly reduces peak RH levels in Tampa. In Phoenix and Saskatoon there is a small reduction during some hours of the year and a slight increase during some hours of the year. This is due to their dry climates and the need to increase RH if it is too low. The addition of the energy wheel reduces the number of people that are dissatisfied with PAQ within the space in Tampa. In Saskatoon and Phoenix there is less of an effect on the percent dissatisfied with the PAQ. By using an energy wheel, the total energy consumed by the HVAC system is reduced in Saskatoon, Phoenix and Tampa. There is a significant reduction in the size of the heating equipment in Saskatoon and in the size of the cooling equipment in Phoenix, Tampa and Saskatoon. A cost analysis shows that the HVAC system including an energy wheel has the least life cycle costs in Saskatoon and Tampa. In Phoenix the life cycle cost is nearly the same for the energy wheel and the case without the energy wheel. In Vancouver, the energy wheel has a nefligible impact on the indoor RH, PAQ, energy consumption and life cycle cost. [ABSTRACT FROM AUTHOR]