Buildings

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Energy Efficient ◽  
Energy Use ◽  
Fossil Fuel ◽  
Local Climate ◽  
Heating And Cooling ◽  
The Difference ◽  
As If

Most of the energy used by buildings goes into heating and cooling. For small buildings, such as houses, heat transfer by conduction through the sides is as much as, if not greater than, the heat transfer from air exchanges with the outside. For large buildings, such as offices and factories, the greater volume-to-surface ratio means that air exchanges are more significant. Lights, people and equipment can make significant contributions. Since the energy used depends on the difference in temperature between the inside and the outside, local climate is the most important factor that determines energy use. If heating is required, it is usually more efficient to use a heat pump than to directly burn a fossil fuel. Using diffuse daylight is always more energy efficient than lighting up a room with artificial lights, although this will set a limit on the size of buildings.

scholarly journals Comparison of Building Simulation Methods for Modeling Apartment Balconies

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3955
Author(s):  
Yonghan Ahn ◽  
Hanbyeol Jang ◽  
Junghyon Mun
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Parameter Analysis ◽  
Interior Space ◽  
Heating And Cooling ◽  
Significant Difference ◽  
Calculation Results ◽  
Infiltration Parameter ◽  
The Difference ◽  
Heating And Cooling Load

The purpose of this study is to compare the load calculation results by a model using the air changes per hour (ACH) method and a model using an airflow network (AFN) and to ascertain what causes the difference between the two models. In the basic case study, the difference in the heat transfer distribution of the model in the interior space was investigated. The most significant difference between the two models is the heat transfer that results from infiltration. Parameter analysis was performed to investigate the relationship between the difference and the environmental variables. The result shows that the greater the difference is between the air temperature inside the balcony and the outdoor air temperature, and the greater the air flows from the balcony to the residential area, and the greater the heating and cooling load difference occurs. The analysis using the actual weather files of five domestic cities in South Korea rather than a virtual case shows that the differences are not so obvious when the wind blows at a constant speed throughout the year, but are dominant when the wind does not blow during the night and is stronger alongside the occurrence of sunlight during the day.

scholarly journals ENERGY EFFICIENCY IN RESIDENTIAL BUILDINGS, LESS STRAIGHT FORWARD THEN PRESUMED

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Hugo Hens
Keyword(s):  
Energy Efficiency ◽  
Energy Efficient ◽  
Energy Use ◽  
Low Voltage ◽  
Residential Buildings ◽  
Primary Energy ◽  
Heating And Cooling ◽  
Net Zero ◽  
Energy Conserving ◽  
New Construction

Since the 1990s, the successive EU directives and related national or regional legislations require new construction and retrofits to be as much as possible energy-efficient. Several measures that should stepwise minimize the primary energy use for heating and cooling have become mandated as requirement. However, in reality, related predicted savings are not seen in practice. Two effects are responsible for that. The first one refers to dweller habits, which are more energy-conserving than the calculation tools presume. In fact, while in non-energy-efficient ones, habits on average result in up to a 50% lower end energy use for heating than predicted. That percentage drops to zero or it even turns negative in extremely energy-efficient residences. The second effect refers to problems with low-voltage distribution grids not designed to transport the peaks in electricity whensunny in summer. Through that, a part of converters has to be uncoupled now and then, which means less renewable electricity. This is illustrated by examples that in theory should be net-zero buildings due to the measures applied and the presence of enough photovoltaic cells (PV) on each roof. We can conclude that mandating extreme energy efficiency far beyond the present total optimum value for residential buildings looks questionable as a policy. However, despite that, governments and administrations still seem to require even more extreme measurements regarding energy efficiency.

Energy Efficient Residential Block Design

2013 ◽  
pp. 1027-1046 ◽  
Author(s):  
Hakan Hisarligil ◽  
Sule Karaaslan
Keyword(s):  
Energy Efficient ◽  
Energy Use ◽  
Block Design ◽  
Methodological Approach ◽  
Sustainable Urban Development ◽  
Efficient Design ◽  
Heating And Cooling ◽  
Building Energy Analysis ◽  
Cooling Loads ◽  
User Friendly

This chapter presents a methodological approach to residential block design for sustainable urban development for hot-summer and cold-winter climates. Taking Ankara as a case, its focus is on developing an energy efficient design process as regards residential block geometry with optimum performance for both climate and energy use. The numerous variables analyzed are orientation, building geometry and envelope, heating and cooling loads of buildings, and microclimatic conditions including solar radiation, air, and wall temperature, and wind speed. It is also important in this study to demonstrate the potential use of “free and user-friendly” simulation tools for such analysis in the early design phase for those who are not experts but have moderate knowledge of urban microclimate and energy. For this aim Weather Tool v2.00 for climate and passive design analysis, CASAnova 3.0 for building energy analysis, and ENVI-met 3.0 for microclimatic analysis are used.

Ground Source Heat Pump System: A Review of Current Status in China

2014 ◽  
Vol 7 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Rong Wan ◽  
Dequan Kong ◽  
Hong Guo
Keyword(s):  
Heat Pump ◽  
Energy Use ◽  
Current Status ◽  
Ground Source Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Urban Buildings ◽  
Ground Source ◽  
Future Work

This paper discusses the research and the state-of-art practices on ground source heat pump systems (GSHP) in China. It introduces the Chinese patents on GSHP. The GSHP development policies of China, including incentive mechanism, relevant codes and regulations, are also introduced. In addition, this paper discusses and summarizes the shortages and imperfects of the current research of the GSHP system and gives some recommendations for future work. At last, the authors give some advice for the development of ground source heat pump. For more reliable statistics on geothermal energy use, the obligation to supply an installation report to the relevant authority should also be imposed on the rural buildings besides urban buildings. GSHP systems are suitable for heating and cooling of buildings and so could play a significant role in reducing CO2 emissions.

Design and Performance of the Van Geet Off-Grid Home

2004 ◽  
Vol 126 (2) ◽  
pp. 738-743 ◽  
Author(s):  
C. Dennis Barley ◽  
Paul Torcellini ◽  
Otto Van Geet
Keyword(s):  
Computer Simulation ◽  
Energy Efficient ◽  
Performance Monitoring ◽  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Hot Water ◽  
Domestic Water ◽  
Heating And Cooling ◽  
And Performance

The Van Geet home near Denver, Colorado, demonstrates the successful integration of energy conservation measures and renewable energy supply in a beautiful, comfortable, energy-efficient, 295-m23,176-ft2 off-grid home in a cold, sunny climate. Features include a tight envelope, energy-efficient appliances, passive solar heating (direct gain and Trombe wall), natural cooling, solar hot water, and photovoltaics. In addition to describing this house and its performance, this paper describes the recommended design process of (1) setting a goal for energy efficiency at the outset, (2) applying rules of thumb, and (3) using computer simulation to fine-tune the design. Performance monitoring and computer simulation are combined for the best possible analysis of energy performance. In this case, energy savings are estimated as 89% heating and cooling (compared to 95 MEC), 83% electrical, and nearly 100% domestic water heating. The heating and cooling energy use is 8.96kJ/°Cs˙days˙m20.44Btu/°Fs˙days˙ft2.

Design Optimization of Energy Efficient Office Buildings in Tunisia

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Pyeongchan Ihm ◽  
Moncef Krarti
Keyword(s):  
Energy Efficiency ◽  
Energy Efficient ◽  
High Performance ◽  
Energy Use ◽  
Cost Effective ◽  
Energy Performance ◽  
High Energy ◽  
Office Buildings ◽  
Optimization Approach ◽  
Heating And Cooling

Optimal and cost-effective energy efficiency design and operation options are evaluated for office buildings in Tunisia. In the analysis, several design and operation features are considered including orientation, window location and size, high performance glazing types, wall and roof insulation levels, energy efficient lighting systems, daylighting controls, temperature settings, and energy efficient heating and cooling systems. First, the results of the optimization results from a sequential search technique are compared against those obtained by a more time consuming brute-force optimization approach. Then, the optimal design features for a prototypical office building are determined for selected locations in Tunisia. The optimization results indicate that utilizing daylighting controls, energy efficient lighting fixtures, and low-e double glazing, and roof insulation are required energy efficiency measures to design high energy performance office buildings throughout climatic zones in Tunisia. In particular, it is found that implementing these measures can cost-effectively reduce the annual energy use by 50% compared to the current design practices of office buildings in Tunisia.

Cooling and heating rate limits of a reversed reciprocating ericsson cycle at steady state

2000 ◽  
Vol 214 (1) ◽  
pp. 75-85 ◽  
Author(s):  
D A Blank ◽  
C Wu
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pump ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Optimized Design ◽  
Cooling Mode ◽  
Working Fluids ◽  
Heating And Cooling

The optimal cooling and heating rates for the reversed reciprocating Ericsson cycle with ideal regeneration are determined for heat pump operations. These limiting rates are based on the upper and lower thermal reservoir temperature bounds and are obtained using time and entropy minimization procedures from irreversible thermodynamics. Use is made of time symmetry (a second law constraint) to minimize cycle time. This optimally allocates the thermal capacitances of the cycle and minimizes internal cycle entropy generation. Although primarily a theoretical work, a very practical and extensive parametric study using several environmentally friendly working fluids (neon, nitrogen and helium) is included. This study evaluates the relative contributions of various system parameters to rate-optimized design. The coefficient of performance (COP), and thus the quantity of cooling or heating for a given energy input, is the traditional focus; instead this work aims at the rate of cooling or heating in heat pumps under steady state conditions and using ideal gases as their working substances. The results obtained provide additional criteria for use in the study, design and performance evaluation of employing Ericsson cycles in refrigeration, air conditioning and heat pump applications. They give direct insight into what is required in designing a reversed Ericsson heat pump to achieve maximum heating and cooling rates. The choices of working fluids and pressure ratios were found to be very significant design parameters, together with selection of regenerator and source—sink heat transfer parameters. The parameter most influencing both the heating and cooling mode COPs and the heat transfer rates was found to be the heat conductance of the thermal sink.

scholarly journals Modeling and Simulation Performance Evaluation of a Proposed Calorimeter for Testing a Heat Pump System

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4589 ◽  
Author(s):  
Amoabeng ◽  
Lee ◽  
Choi
Keyword(s):  
Energy Consumption ◽  
Modeling And Simulation ◽  
Heat Pump ◽  
Energy Efficient ◽  
Residential Buildings ◽  
Test Chamber ◽  
High Energy ◽  
Heat Pumps ◽  
Pump System ◽  
Heating And Cooling

The energy consumption for heating and cooling in the building sector accounts for more than one-third of total energy used worldwide. In view of that, it is important to develop energy efficient cooling and heating systems in order to conserve energy in buildings as well as reduce greenhouse gas emissions. In both commercial and residential buildings, the heat pump has been adopted as an energy efficient technology for space heating and cooling purposes as compared to conventional air conditioning systems. However, heat pumps undergo standard testing, rating, and certification procedures to ascertain their system performance. Essentially, the calorimeter for testing heat pumps has two test chambers to serve as a heat source and heat sink to control and maintain the test conditions required to simulate the heat pump indoor and outdoor units, simultaneously. In air-to-air heat pump units, the conventional calorimeter controls the air temperature and humidity conditions in each test chamber with separate air handling units consisting of a refrigerator, heater, humidifier, and supply fan, which results in high energy consumption. In this study, using dynamic modeling and simulation, a new calorimeter for controlling air conditions in each test chamber is proposed. The performance analysis based on simulation results showed that the newly proposed calorimeter predicted at least 43% energy savings with the use of a heat recovery unit and small refrigerator capacity as compared to the conventional calorimeter that utilized a large refrigerator capacity for all the weather conditions and load capacities that we investigated.

scholarly journals Economic carbon cycle feedbacks may offset additional warming from natural feedbacks

2018 ◽  
Vol 116 (3) ◽  
pp. 759-764 ◽  
Author(s):  
Dawn L. Woodard ◽  
Steven J. Davis ◽  
James T. Randerson
Keyword(s):  
Economic Activity ◽  
Radiative Forcing ◽  
Energy Use ◽  
Fossil Fuel ◽  
Climate Feedback ◽  
Carbon Intensity ◽  
Similar Amount ◽  
Carbon Sinks ◽  
Economic Productivity ◽  
Heating And Cooling

As the Earth warms, carbon sinks on land and in the ocean will weaken, thereby increasing the rate of warming. Although natural mechanisms contributing to this positive climate–carbon feedback have been evaluated using Earth system models, analogous feedbacks involving human activities have not been systematically quantified. Here we conceptualize and estimate the magnitude of several economic mechanisms that generate a carbon–climate feedback, using the Kaya identity to separate a net economic feedback into components associated with population, GDP, heating and cooling, and the carbon intensity of energy production and transportation. We find that climate-driven decreases in economic activity (GDP) may in turn decrease human energy use and thus fossil fuel CO2 emissions. In a high radiative forcing scenario, such decreases in economic activity reduce fossil fuel emissions by 13% this century, lowering atmospheric CO2 by over 100 ppm in 2100. The natural carbon–climate feedback, in contrast, increases atmospheric CO2 over this period by a similar amount, and thus, the net effect including both feedbacks is nearly zero. Our work highlights the importance of improving the representation of climate–economic feedbacks in scenarios of future change. Although the effects of climate warming on the economy may offset weakening land and ocean carbon sinks, a loss of economic productivity will have high societal costs, potentially increasing wealth inequity and limiting resources available for effective adaptation.

scholarly journals A Review of Underground Soil and Night Sky as Passive Heat Sink: Design Configurations and Models

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2941 ◽  
Author(s):  
Rachana Vidhi
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Heat Sink ◽  
Heat Exchangers ◽  
Energy Use ◽  
Ambient Air ◽  
Radiative Cooling ◽  
Cooling Systems ◽  
Heating And Cooling ◽  
Night Sky

Energy consumption for heating and cooling constitute the majority of the energy use for building loads. Using passive cooling systems to reduce the energy consumption or to make the process more efficient can be very beneficial. Ground coupled heat exchangers and night sky radiative cooling systems have been used for centuries to achieve cooling and ice making. Ground coupled heat exchangers use the temperature difference between underground soil and ambient air or water for heat transfer between the soil and the fluid passing through buried pipes. Night sky radiative cooling takes advantage of the night sky as the coldest heat sink available for heat transfer with any surface. Use of these simple designs with the modern cooling/heating systems has the potential for a major impact on the heating and cooling needs. This review paper describes the various designs, configurations and applications of these systems as well as determining the parameters that impact their performance.

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