Lessons learned from the Pefki solar village in Athens, nearly 20 years on

Solar Village 3 in Pefki, Athens, was part of an ambitious program, with active and passive solar systems providing space and water heating for 1750 inhabitants, designed in the early 80's, and inhabited from the late 80's. This paper focuses on passive solar systems applied to a number of the buildings. A survey highlighted the cases of trombe water benches and conservatories as the most frequently, poorly operated systems. Over time this led to a lack of belief by the occupants in the passive systems. Building simulation indicated a much higher cooling load than originally designed for, combined with recent warmer summers and poor maintenance and operation, have led to the present case that many homes have installed air conditioning. Plans for district heating will improve heating provision for residents and reduce CO2 emissions but a lack of a maintenance strategy for the passive systems will surely lead to their increased neglect

Solar Energy Resource Potential in Alaska

Solar energy applications are receiving attention in Alaska as in much of the rest of the country. Solar energy possibilities for Alaska include domestic water heating, hot-water or hot-air collection for space heating, and the use of passive solar heating in residential or commercial buildings. As a first analysis, this study concentrated on applying solar energy to domestic hot-water heating needs (not space heating) in Alaska, and an analysis of solar hot-water heating economics was performed using the F-CHART solar energy simulation computer program. Results indicate that solar energy cannot compete economically with oil-heated domestic hot water at any of the five study locations in Alaska, but that it may be economical in comparison with electrically heated hot water if solar collector systems can be purchased and installed for $20 to$25 per square foot.This work was made possible by a grant from the Solar Planning Office, West, 3333 Quebec, Denver, Colorado. It was performed as the Alaskan response to a western regional solar energy planning grant from the U. S. Department of Energy. The authors wish to acknowledge the support and cooperation of the Alaska State Department of Commerce, Division of Energy and Power Development, through whose efforts the grant was made available, especially Clarissa Quinlan, Grant Peterson, and Don Markle

Energy Fact Sheet: Residential Solar Heating

Heating a residence and the domestic water supply with solar energy is technically feasible in Kentucky. However, it is not feasible to provide 100 percent of the heat requirements. Some backup system is needed for continuous heat during cloudy weather and the cold part of winter. Both passive and active solar heating systems are technically feasible

Passive solar solutions for buildings: Criteria and guidelines for a synergistic design

Passive solar system design is an essential asset in a zero-energy building perspective to reduce heating, cooling, lighting, and ventilation loads. The integration of passive systems in building leads to a reduction of plant operation with considerable environmental benefits. The design can be related to intrinsic and extrinsic factors that influence the final performance in a synergistic way. The aim of this paper is to provide a comprehensive view of the elements that influence passive solar systems by means of an analysis of the theoretical background and the synergistic design of various solutions available. The paper quantifies the potential impact of influencing factors on the final performance and then investigates a case study of an existing public building, analyzing the effects of the integration of different passive systems through energy simulations. General investigation has highlighted that latitude and orientation impact energy saving on average by 3–13 and 6–11 percentage points, respectively. The case study showed that almost 20% of the building energy demand can be saved by means of passive solar systems. A higher contribution is given by mixing direct and indirect solutions, as half of the heating and around 25% of the cooling energy demand can be cut off

Evolution of the American Zero Energy House

Interest in reducing energy use in buildings began in the U.S. in the 1930 with work at the Massachusetts Institute of Technology on solar heated structures. With the energy crises in the 1970s, efforts were made to reduce energy use in U.S. homes. Passive solar design involved insulated south oriented glazing systems, Trombe walls, sunspaces, flat plate collectors; thermal mass and optimally designed overhangs. It was discovered that by reducing building cooling and heating needs through energy conservation while implementing passive solar strategies the lowest energy use at a lower incremental cost could be achieved. Super-insulated homes were successful at minimizing heat loss and gain and the subsequent load on mechanical systems, but interest subsided as energy prices dropped in the 1980s. The passive solar homes and super-insulation movements, addressed passive heating and cooling, but other home energy end uses were not addressed. Throughout the late 1980s, the cost of solid state solar electricity production with photovoltaic cells declined and become affordable for individual house distributed generation. This paper is a survey of the evolution of the Zero Energy House in the U.S. and the related technologies from its experimental beginnings to its realization in several recent projects.&nbsp

F-Chart Method For Design Domestic Hot Water Heating System In Ayer Keroh Melaka

Renewable energy is an alternative approach of energy supply that meets the needs of the present generations without compromising the ability of future generations to meet their own needs. One type of renewable energy is solar energy. Solar energy systems convert solar energy into useful energy. In designing a solar collector, there are predictable and unpredictable parameters that are considered. Predictable parameters include performance characteristics of collector and mainly concern weather data such as solar radiation, ambient temperature, wind speed, direction, and other parameters is performance characteristics of collectors. This work analysed the use of the f-chart method in design liquid solar heating systems due to its simplicity and ability to estimate the fraction of total heating load supplied by the solar heating system. This method is very commonly used in designing for both active and passive solar heating systems, especially in selecting sizes and type of solar collectors that provide the hot water and heating loads. In this research, the data of the project is analysed to calculate based on the f-chart graph. The results show that the area in Melaka around the vicinity of Ayer Keroh is suitable for the installation of the flat-plate solar collector. The total annual heating load of domestic hot water in Melaka is 9.55 GJ and the annual fraction of the load supplied by solar energy is 78.42% which is suitable for implementation and installation in Ayer Keroh, Melak

Numerical studies on laminar, transitional and turbulent convective airflows in channels with generalised geometry, including applications to thermal-ventilation passive systems

The flows induced by natural convection appear in many engineering problems. Configurations formed by heated plates where these processes occur, were the topic of intense study in past years. However, new systems with a different constructive disposition and applications in several fields (bioclimatic architecture, electronic cooling, nuclear energy cooling systems) are at the moment of great interest. Since typical applications of buoyancy-driven airflows in smooth vertical channels are usually in small-scale devices (i.e. in electronic cooling equipment), most investigations were carried out for laminar flows. As a consequence of the great scale of certain passive ventilation systems, as solar chimneys, Trombe walls, or roof collectors, the flow established becomes transitional or even fully turbulent. The regarded geometries frequently involve structures based on converging and sloped channels formed by heated plates, where buoyancy-driven flows take place. Therefore, the study of problems such as the transition to turbulent regime or flows with walled-channel geometries including sloped and converging walls are key to assertively find out the real heating transmission existing in these new systems in a more realistic manner. Nowadays, the need to achieve human comfort by passive heating and ventilation techniques is greater as is the requirement for energy saving. Passive solar systems are the basic elements of bioclimatic design and they do not involve the use of mechanical or electrical devices. The Trombe Wall is the primary example of the technique called indirect gain, whose typical configuration is usually formed by a thick, darkened, masonry wall and a glazed wall. In ventilation applications, other passive systems, called thermosyphons, heat syphons or solar chimneys, can yield natural motions of air due to the induced temperature differences by solar heating. Although several reported works provided useful results for the analysis and design of passive solar devices in buildings, these works cannot determine the necessary details of convection for numerical simulations. Furthermore, as an important lack of design correlations is detected, it is necessary to carry out a systematic study that supplied the heat transfer coefficient and the mass-flow rate as a function of relevant parameters, for several configurations

Net Zero Residential Design for Solar CalPoly

The Department of Energy (DOE) confirmed Team Solar Cal Poly from California Polytechnic State University, San Luis Obispo, as a competitor in the 2015 Solar Decathlon in February 2014. The Solar Decathlon is a biennial collegiate competition to construct a net-zero home and operate it for a week of “normal use”. Solar Cal Poly needed assistance with passive and active HVAC systems for the design, and thermal load models. The competition will take place in Irvine, CA [33.67⁰, 117.82⁰ W] from September 27 – October 3, 2015. After the completion, a potential final location for the house will be Santa Ynez, CA [34.61⁰ N, 120.09⁰ W]. Ms. Willis assisted with a climate study for both locations and research passive and active HVAC systems and design elements for Team Solar Cal Poly. She modeled the final summer design in DesignBuilder to calculate the heating and cooling loads. The heating load was calculated to be 26.7 kBTU/h. The cooling load was calculated to be 2-tons. A mini-split HVAC system was selected for the final summer design based off the calculated heating and cooling loads. For this design, the Fujitsu Hybrid Halcyon Flex met the minimum requirements, and was a multi-zone system that could condition all three major spaces of the design. This report provides a summary of information and the basic design process for future Solar Decathlon designs considerations

Passive systems for buildings using buoyancy-driven airflows

The need for countries to become less dependent on fossil fuels has been a determining factor in recent years due to increasing energy and comfort concerns in modern building design. Therefore, the maximization of the use of renewable energies, like the sun, and the use of natural energy flows become strategies to explore. There are already passive building systems that show interesting performances. Different studies have proved that the above-mentioned systems can lead to important energy savings. However, these systems have their limitations and new innovative building solutions are needed, mainly in the field of passive solar energy collection and natural ventilation strategies. Furthermore, building envelopes face nowadays a new paradigm in which buildings need to be more reactive and adaptive to external climate changes and indoor thermal comfort demands. Hence, this paper makes a review of the most recent patents on building solar air systems that make use of solar energy to induce the buoyancy effect for heating, cooling and ventilating. The patents presented demonstrate the increasing tendency in the development of building passive solutions that can satisfy, in just one system, more than one role: heating, cooling and ventilation.The present paper was performed within the framework of a research project on Low Energy/High Comfort Building Renewal, PTDC/ECM/67373/2006, sponsored by the Portuguese Foundation for Science and Technology (FCT)

Optimal Control Strategies for Passive Heating and Cooling Elements Reduce Loads by Two-Thirds in the Adaptive Reuse of a San Francisco Bay Area Office

Housing crises in urban centers and growing climate concerns are encouraging city planners and building owners to explore the conversion of commercial buildings into energy-efcient dwellings. Passive solar heating, shading, and natural ventilation are attractive in such adaptive reuse projects since they minimize operational energy, but they sufer from the perception of limited efectiveness, and passive heating is ofen disregarded entirely in cloudy climates. At the same time, passive heating has recently shown promise in the cloudy winters of western Oregon and upstate New York, allowing the San Francisco Bay area to provide an excellent opportunity for further exploration. Passive cooling measures, in turn, are essential to prevent overheating. Tis work investigates the conversion of a brick ofce space in Berkeley, CA into a residential lof, using movable insulation, operable windows, thermal mass, and shading to diminish the need for mechanical conditioning to the extent possible. To determine this extent, preliminary explorations in EnergyPlus were followed by Hooke-Jeeves and particle-swarm optimizations of control thresholds, following feld-validated techniques for passive heating and cooling simulation. Optimized parameters included skylight tilt; schedules for movable insulation, shading, and natural ventilation; and thermal mass quantity, each required to minimize annual sensible heating and cooling energy while maintaining adaptive thermal comfort. With optimal control, over half of the heating need could be met by passive solar collection and storage; likewise, most cooling (~80%) could be accomplished passively if shading and natural ventilation were well-controlled. Without these controls, most of the beneft was lost. We therefore propose replacing the term “passive” with “well-controlled passive” to refect the importance of controls in sensing conditions and adjusting movable elements to maximize the performance of these systems