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Liquid Desiccant Air Conditioning and Dehumidification (LDAC) has been emerging in the past 10 to 15 years as an energy-saving alternative design for applications that require high moisture removal and a Cleantech solution that has the potential to provide significant energy savings when applied to more broad markets. Buildings are the primary users of electricity in the U.S., consuming about 75% of the total electricity produced and about 40% of all U.S. primary energy use and associated greenhouse gas (GHG) emissions. A substantial portion of that energy is used for air conditioning and dehumidification. Furthermore, the U.S. Department of Energy (DOE) reports that U.S. buildings account for 35% of the U.S. carbon dioxide emissions that drive the climate crisis. One specific application that requires significant moisture removal is the indoor cultivation of legal cannabis. It is estimated by the DOE that by the end of this decade, electrical energy usage by indoor cannabis operations will be on par with the electrical energy consumed by either data centers or for the recharging of electrical vehicles. More recent projections indicate cannabis sales are expected to double from 2021 to 2030. As such, more efficient and economical methods of climate control are necessary for more widespread application in cannabis operations to reduce the energy requirements. The added emphasis should be on methods to first reduce the energy required before building the electrical generating infrastructure to support such growing industries. Climate control of indoor cannabis cultivation is one such aspect where energy-efficient air conditioning and dehumidification can contribute to reducing the projected energy usage by end of this decade. This paper gives an overview of a standalone LDAC system and a hybrid LDAC combined with an air handling unit. This paper will present indoor grow room case studies from a side-by-side installation of a hybrid LDAC unit and Desiccant Wheel (DW) air handling system in two identical cannabis grow rooms. Integration with a Combined Heat and Power (CHP or cogeneration) plant onsite supplying energy for both the technologies will be examined. Further, comparative energy analyses of LDAC, DW technology, and other widely used technologies in the HVAC indoor growing environment will be discussed. This will be the first comprehensive, side-by-side performance and energy analysis of competing desiccant (LDAC and DW) technologies in a controlled, indoor agriculture environment. [ABSTRACT FROM AUTHOR]

The climate crisis currently being faced by humanity is going to increase extreme weather events which are likely to make long-duration power outages for communities increase in frequency and duration. Microgrids are an important part of electrical resilience for connected communities during power outages. They also can have transactive potential to save energy on electric loads through coordinating distributed energy resources. Microgrids are expensive though. Making electric load coverage available nearly 100% of the time given known design basis threats and component failure statistics is one of the largest drivers of cost. Such high availability is non-negotiable for critical applications such as life saving equipment in a hospital but could perhaps be compromised for less critical loads. This paper documents an analysis that used the Microgrid Design Toolkit and EnergyPlus simulation results with two energy retrofit options exercised. The results show how increasing energy efficiency and reducing availability to 90% and 80% reduced the calculated price of a photovoltaic and battery storage microgrid in a New Mexico neighborhood by 63% and 70%, respectively. A microgrid with 80% availability with 48-hour islanded run-time capability is therefore suggested as a low-cost method for accelerating microgrid infrastructure penetration into the residential sector. Such an "underbuilt" microgrid will significantly increase resilience even though it will not guarantee energy security for the non-critical applications in residential households. This will in turn accelerate the growth of storage potential across communities providing greater grid flexibility. The results of the study also show how increased insulation applied to the proposed residential community can be less expensive than creating a larger microgrid that carries larger electric loads. The likelihood that energy retrofits are a better investment than a larger microgrid is inversely proportional to availability. Here, availability is a metric equal to the percentage of the demand load served by the microgrid during power outages, not including the startup period. [ABSTRACT FROM AUTHOR]

The paper deals with the integrated building design process in the French tropical island of La Reunion throughout the design of the first Net Zero Energy Building named ENERPOS. So far the design process in France is not well adapted to the design of zero energy buildings and does not allow the easy achievement of energy efficient buildings. A reorganization from the brief to the construction of the building itself is therefore necessary. Several reasons can explain this statement. First, no thermal standards are mandatory in Reunion Island as most of the French overseas territories. This leads to the construction of energy consuming buildings. However, a guideline named PERENE has been set-up but the prescriptions are not mandatory. They concern the thermal conception of buildings as well as the energy performance of buildings and are specific to each climatic zone that has been defined in PERENE. Despite that, the PERENE rules give only a minimum level of performance and can not be considered as the optimum design. Second, the lack of knowledge in the HVAC design practices about the last design tools and the lack of discussion between the people involved in the design process - i.e. the architect and the engineers is an obvious weakness for optimizing the passive design of the envelope and the systems. In some cases, the design teams selected by public owners - the Regional Council, the University and the City Councils have most of the time an overall good level of knowledge but unfortunately the brief of the building is not accurate enough in terms of objectives and energy performance requirements to meet. The paper will present the state of the art in France in terms of design process from the brief until the completion of the building. Then the adopted methodology will be introduced and applied to the case study of the ENERPOS building. The design stage has focused on the development of new methods for the design of zero net energy buildings in French tropical overseas territories. As the building has been completed in 2008, the lessons learned will be presented as well. [ABSTRACT FROM AUTHOR]

Heat pumps provide an efficient heating method; however they suffer from sever capacity and performance degradation at low ambient conditions. This has deterred market penetration in cold climates. There is a continuing effort to find an efficient air source cold climate heat pump that maintains acceptable capacity and performance at low ambient conditions. Systematic optimization techniques provide a reliable approach for the design of such systems. This paper presents a step-bystep approach for the design optimization of cold climate heat pumps. We first start by describing the optimization problem: objective function, constraints, and design space. Then we illustrate how to perform this design optimization using an open source publicly available optimization toolbox. The response of the heat pump design was evaluated using a validated component based vapor compression model. This model was treated as a black box model within the optimization framework. Optimum designs for different system configurations are presented. These optimum results were further analyzed to understand the performance tradeoff and selection criteria. The paper ends with a discussion on the use of systematic optimization for the cold climate heat pump design. [ABSTRACT FROM AUTHOR]

Energy efficiency has become increasingly important in the data center industry, driven by rising energy prices, environmental legislation, corporate social responsibility pressures, and competition. Energy efficiency is part of sustainability, however, consideration of other aspects such as the embodied environmental impact of materials, components, and systems is needed for a holistic view. Life-cycle assessment (LCA) is a useful methodology that examines wider environmental impact including areas of protection such as climate change, ecosystem quality, human health, and resource depletion. The industry is starting to become more aware of these issues and is developing metrics to quantify performance. This paper describes key data center sustainability issues identified by the life-cycle assessment of data centers and proposes how the industry could approach its environmental responsibilities in order to capitalize on the business opportunity as well as demonstrating sustainable leadership. [ABSTRACT FROM AUTHOR]

Today designers, as a result of climate change concerns, are being asked to consider new lower Global Warming Potential (GWP) unsaturated hydrofluorocarbon (HFO) refrigerants and blends of hydrofluorocarbon (HFC) with HFO refrigerants, some of which are slightly flammable under certain conditions, as well as the less than desirable natural refrigerants. In the lower GWP refrigerant future, the world will adopt refrigerants with less than optimal properties in some applications. A single refrigerant, such as R-22 or R-410A that addresses a large area of market demands for a safe, high efficiency refrigerant with lowest cost products may not be available. In general, product designs may have to compromise on efficiency, safety and reliability which could lead to increased product costs for consumers and may result market fragmentation by refrigerant type to enable this future. In some instances, new HFO refrigerants will be able to maintain society's demands for efficiency, safety and reliability while balancing the need for lower direct GWP impact. In other instances, acceptance of significant product and application design compromises, such as the use of flammable refrigerants, will be required or more costly solutions will need to be considered because of safety, efficiency, capacity or reliability constraints. Natural refrigerants will gain more attention and expanded use when efficiency, safety and reliability can be delivered at a reasonable cost to consumers. Some natural refrigerants being considered and adopted today will be phased out because of ever increasing efficiency needs. This paper will review the various low GWP refrigerant options being proposed and weigh the compromises they present for their future adoption. [ABSTRACT FROM AUTHOR]

With utility costs projected to increase in the near future, many developers and planners are beginning to view energy conservation measures more seriously. Energy modelers are going to be consulted more frequently in order to determine the feasibility of implementing these measures into future projects. However, before justified decisions can be made regarding incorporating energy conservation measures, a determination must be made on how accurate current energy modeling predications are based on actual measured data. This paper will address a study performed on four facilities comparing projected energy use versus measured data. The facilities encompass a wide range of building type, HVAC systems, climate regions, and operation schedules. The data provided will assist developers and planners with understanding the benefits of energy modeling and offer ideas to help further reduce discrepancies between modeled and metered data. [ABSTRACT FROM AUTHOR]

The U.S. Army Corps of Engineers, in collaboration with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL), academia, and private sector subject matter experts, recently completed an energy study to evaluate potential site and source energy-use reduction in new Army buildings. The study was completed in response to the mandates for energy savings in federal buildings enacted by the U.S. Energy Independence and Security Act of 2007 (U.S. Congress 2007). The building types studied included an Unaccompanied Enlisted Personnel Housing (UEPH or barracks), a brigade headquarters (administrative building), a company operation facility, a maintenance facility, and a dining facility (DFAC). The study was conducted for representative locations in all 15 DOE identified climate zones in the United States with building designs adapted to these climatic conditions. This paper presents the results of the energy analysis for a typical Army dining facility. It discusses energy efficiency measures and combinations used to reduce both internal and external loads on the building and overall energy use. The largest load in a DFAC is the cooking, and the currently available best-in-class kitchen equipment is included in the final design. The potential site energy savings compared to the energy code range from 21% to 38%. The potential source energy savings compared to Commercial Building Energy Consumption Survey ranges from 37% to 42%. Additional savings may be obtained if an efficient cogeneration system is used and the building is considered as a part of the building cluster or community to fully utilize the energy from the cogeneration system. [ABSTRACT FROM AUTHOR]

This paper explores the laboratory performance of five integrated Heat Pump Water Heaters (HPWHs) across a wide range of operating conditions representative of US climate regions. Laboratory results demonstrate the efficiency of this technology under most of the conditions tested and show that differences in control schemes and design features impact the performance of the individual units. These results were used to understand current model limitations, and then to bracket the energy savings potential for HPWH technology in various US climate regions. Simulation results show that HPWHs are expected to provide significant energy savings in many climate zones when compared to other types of water heaters (up to 64%, including impact on HVAC systems). [ABSTRACT FROM AUTHOR]

This paper will examine the challenges for energy-efficient ventilation that shopping malls present. In these buildings, the retail stores are often heated, cooled and ventilated separately from the mall central spaces, yet are connected to them by large, open doorways through which natural air exchanges occur, hence inextricably linking the two spaces. However, the central spaces of the mall are usually deemed to have the potential for more relaxed ranges of interior conditions than the retail stores adjacent to them, and regulatory requirements for these two types of space can also differ. The façade and roof access to the central spaces of malls mean that they have the potential to be ventilated naturally, or with a hybrid ventilation scheme. The extent to which this is beneficial depends on the local climate, as well as aspects of mall design such as glazing extents, and potential for low-level and high-level ventilation openings. This study examines potential strategies for reducing energy use in such buildings by means of natural and/or hybrid ventilation of the mall central spaces. These strategies need to be formulated with the aim of reducing the whole building energy consumption, taking into account both the heating and cooling demands for the central space, and those of the adjacent retail stores interacting fluid mechanically with it. A numerical thermodynamic model has been developed to investigate this with respect to energy consumption and internal comfort of a hypothetical mall under various ventilation strategies. The influence of ventilation strategy on cost of plant (capital and maintenance) will also be discussed. [ABSTRACT FROM AUTHOR]

Northern climate like the one in Montreal 4,557 DD (SI) - (8,200 DD (IMP)) presents huge challenges to the designers to reach Net-Zero Energy buildings. A large amount of the energy required is related to the heating of the outside air and the 24 hours/day, 7 days/week operation. It is not rare to be faced with labs designed a few decades ago which consumes in the order of 2150 kW-h equiv /m²-year (200 kW-h equiv/sq.ft.-year), compared to 540 kW-h equiv / m²-year (50 kW-h equiv / sq.ft.-year) and better for recent labs. This paper presents a list of potential options to improve energy efficiency. Three laboratories are presented with the different measures that were applied in those buildings. [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]

The definition of a good indoor climate is important to the success of a passenger rail coach, not only because it will decide its energy consumption and thus influence its sustainability but also because good comfort for long journeys is essential. The intention is to use the results to optimize the control of the ventilation system to provide an indoor climate that passengers will find comfortable. The results of this study show how passengers' thermal comfort was affected by changing the supplied air conditions. This paper primary discusses and analyzes the simulation of the air flow and thermal patterns in a Subway station. Numerical simulation of a typical model is presented. Modifications were applied to the numerical model to show the improvement of the thermal comfort level. The pre-processor Gambit is used to create the geometric model with parametric features. Commercially available simulation software "Fluent 6.3" is incorporated to solve conservation of mass, momentum and energy in the processing of air distribution, and to analyze turbulence affection combined heat transfer on air distribution. In this thesis work, the socalled standard k-ε turbulence model, one of the most widespread turbulence models for industrial applications, was utilized. Basic parameters included in this work are air temperature, air velocity, relative humidity and turbulence parameters are used for numerical prediction of indoor air distribution. Measurements of air velocity, and temperature were undertaken in a plane perpindicular to the supply diffuser. These values were then compared to the obtained results from the simulated cases. The thermal comfort prediction through this work was based on the PMV (Predicted Mean Vote) model and the PPD (Percentage Predicted Dissatisfied) model, the PMV and PPD were estimated using Fanger's model. [ABSTRACT FROM AUTHOR]

The life-cycle assessment (LCA) methodology is used in this paper to assess the environmental effects of air-handling units (AIIU) over a 20-year life cycle. This assessment is based on quantifying the consumption of resources (energy and materials,), the harmful emissions into the environment (`air; water, and soil), and the potential changes in the environment (climate change, acidification, and ozone production,). A normal AIIU, with a face velocity of 3 m/s (600 fpm), and a small AIIU, with a face velocity of 4 m/s (800 fpm), are investigated with and without two types of air-to-air energy exchangers (plate and rotating wheel). The research demonstrates the following benefits of air-to-air energy exchangers: reduced energy consumption, reduced emissions to the environment, and reduced potential harmful changes in the environment. For both of the AIIUs' studied, these benefits are several times greater than the burdens arising from the production and operation of the AIIU, where the function of the AIIU is to provide 2000 L/s (4200 cfm) of outdoor air to the building space for 2500 h/year, but not to condition this air A larger AIIU with an air-to-air energy exchanger of higher efficiency has the smallest harmful effect on the environment. [ABSTRACT FROM AUTHOR]