Relation between energy consumption and window to wall ratio in high-rise office buildings in Tehran

Development and expansion of high-rise buildings in Iran and the high energy consumption thereof have made adoption of energy consumption reduction strategies a necessity. Building shell and its various parts are the most effective elements in terms of energy consumption. Paying due attention to this fact, the authors of the present article investigate the relation between the window to wall ratio (W.W.R) and energy consumption in high-rise office buildings subjected to climatic conditions in Tehran. The eQUEST software was used to simulate the annual energy consumption of the considered base-case model. In this process, a 100% W.W.R was initially selected for the base-case model. Then, the research tests were conducted at W.W.R of 80%, 60%, 40%, and 20% both generally and individually (side-to-side test). The results showed that the window to wall ratio and annual energy consumption were directly related, i.e., a 20% reduction in the W.W.R could decrease the annual energy consumption in the research base-case model by 17%. Furthermore, the results indicated that the W.W.R affected the energy consumption differently at different sides of the base-case model and that in this respect, the building sides could be prioritized in the following order: south, east, west, and north

Transmission needs across a fully renewable European power system

The residual load and excess power generation of 27 European countries with a 100% penetration of variable renewable energy sources are explored in order to quantify the benefit of power transmission between countries. Estimates are based on extensive weather data, which allows for modelling of hourly mismatches between the demand and renewable generation from wind and solar photovoltaics. For separated countries, balancing is required to cover around 24% of the total annual energy consumption. This number can be reduced down to 15% once all countries are networked together with uncon- strained interconnectors. The reduction represents the maximum possible benefit of transmission for the countries. The total Net Transfer Capacity of the unconstrained interconnectors is roughly twelve times larger than current values. However, constrained interconnector capacities six times larger than the current values are found to provide 97% of the maximum possible benefit of cooperation. This motivates a detailed investigation of several constrained transmission capacity layouts to determine the export and import capabilities of countries participating in a fully renewable European electricity system

Energy saving potential of a hybrid HVAC system with a desiccant wheel activated at low temperatures and an indirect evaporative cooler in handling air in buildings with high latent loads

Air handling in buildings with high latent loads usually requires a high-energy cost to satisfy the user’s thermal comfort needs. Hybrid systems composed of desiccant wheels, DW, and indirect evaporative coolers, IEC, could be an alternative to direct expansion conventional systems, DX systems. The main objective of this work was to determine the annual energy consumption of a hybrid system with a DW activated at low temperatures and an IEC, DW-IEC system, compared to a DX system to serve air in a small building with high latent loads, such as spas. Several annual energy simulations for 6 climate zones were performed, analysing electric energy consumption, seasonal mean coefficient of performance, SCOP, and energy consumption per unit of dehumidified water, Econs, of each system. The simulations were based on experimentally validated models.The annual energy consumption of the DW-IEC system was lower than that of the DX system for the 6 climate zones, achieving significant energy savings, up to 46.8%. These energy savings resulted in better SCOP values for the DW-IEC system. Therefore, the proposed DW-IEC system has high potential to reduce energy costs, achieving the user’s thermal comfort

Impact of adding comfort cooling systems on the energy consumption and EPC rating of an existing UK hotel

Abstract: In light of the recent launch of the Minimum Energy Efficiency Standard and its expected impact on the commercial buildings sector, this study investigated the impact of adding cooling systems on the annual energy consumption, carbon dioxide emissions and energy performance certificate (EPC) rating of an existing UK hotel. Thermal Analysis Software (TAS) was used to conduct the study, and the baseline model was validated against the actual data. As is the current accepted procedure in EPC generating in the UK, the cooling set points of the guest rooms were set to 25 °C, resulting in a small increase in the annual energy consumption and emission rates, but not enough to change the energy performance certificate rating. Also, it was found that an improvement in energy consumption and energy performance certificate rating of the hotel would be achieved if the new systems replaced the existing heating systems in the guest rooms. Further simulations investigated more realistic situations, in which occupants may decide to keep their rooms at cooler temperatures. The results from this round of simulations showed considerable increase in the energy consumption and emissions of the building; however, these results would not be considered in the current approved procedure for EPC generating

Recommendations for 15% Above-Code Energy Efficiency Measures for Commercial Office Building

The file with the "a" is the PowerPoint presentation given at the Hot and Humid Conference.This paper presents an overview of the recommendations for achieving 15% above code energy performance for commercial office buildings complying with ASHRAE Standard 90.1-1999. To accomplish the 15% annual energy consumption reductions, ten measures were considered. After energy savings were determined for each measure, they were then grouped in several groups to accomplish a minimum of 15% total annual energy consumption reduction.Energy Systems Laborator

Recommendations for 15% Above-Code Energy Efficiency Measures for Commercial Office Buildings

This report presents detailed information about the recommendations for achieving 15% above-code energy performance for commercial office buildings complying with ASHRAE Standard 90.1-19991. To accomplish the 15% annual energy consumption reductions, ten measures were considered. After energy savings were determined for each measure, they were then placed in several groups to accomplish a minimum of 15% total annual energy consumption reduction. The analysis in this paper uses the total annual energy consumption of a simulated commercial building to determine the 15% above-code recommendations. The analysis also reports end-use energy use, including: heating, cooling, domestic hot water use, fans, heat rejection, equipment and lighting loads, and miscellaneous loads as defined by the BEPS and BEPU reports from the DOE-2 program. Since the 15% above-code savings use annual energy cost savings, these same measures will report greater savings when compared against total heating and cooling loads, which has been used in other above-code program recommendations

Determination of optimum insulation and cement plaster thickness for bungalow buildings through a simulation-statistical approach using response surface methodology

Insulating interior side of external wall and finishing by cement plaster is one of the most appropriate methods of reducing annual energy consumption in available buildings. The aim of this study is to determine the optimum expanded polystyrene (EPS) and cement plaster thickness for bungalow building in Malaysia. The present study evaluates the effect of different thermal insulation and interior cement plaster thicknesses on the annual cooling energy consumption. Furthermore, the optimum thickness of EPS and plaster is estimated based on wall type and building orientation. Two different types of walls made of concrete and brick are considered. EPS and plaster were used in the range of 20 to 100 mm and 0 to 20mm, respectively. The results show that both thermal insulation and plaster thickness have a direct effect on annual cooling energy consumption, however, the influence of wall thermal insulation thickness is more significant than cement plaster thickness. Further, the optimum EPS thickness decreases with the increment in cement plaster thickness for different orientations and wall types. The optimum EPS thickness ranges from 31.5 mm to 53.1 mm based on wall type, orientation and cement plaster thickness. Utilizing optimum EPS and cement plaster thicknesses can thus reduce annual energy consumption by about 6 to 12 in different directions. © 2019, University of Malaya. All rights reserved