scholarly journals Energy Efficiency of Water Heating Systems in Single-Family Dwellings in Brazil

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1068 ◽  
Author(s):  
Juliana May Sangoi ◽  
Enedir Ghisi

The objective of this paper was to compare primary energy consumption and energy efficiency during the operation phase of different types and combinations of water heating systems in single-family dwellings. Systems with an electric shower, liquefied petroleum gas heater, and solar heater with electric backup were analysed. The analysis was performed by means of computer simulation using EnergyPlus. Three Brazilian cities with different climates were assessed, i.e., Curitiba, Brasília and Belém. The systems were compared in terms of final energy and primary energy consumption. Results showed that systems with an electric shower, which have a lower water flow rate, led to lower primary energy consumption. The solar heating system combined with an electric shower was the option with the lowest energy consumption, and the solar heating system with a heating element in the storage tank was the option that consumed more energy. The systems were sized according to the requirements of the Brazilian energy efficiency labelling for residential buildings, and the efficiency level was compared to the results of primary energy consumption. The electric shower was found to be the third lowest energy consumer, but it was ranked the least energy efficient by Brazilian labelling, while systems with high energy consumption, such as gas heaters and solar heaters with a heating element in the storage tank, were ranked the most energy efficient. Therefore, a review of the requirements and methodology of the Brazilian energy efficiency labelling for residential buildings is recommended in order to encourage the use of truly efficient systems. Public policies that encourage solar heating systems should establish requirements regarding the configuration and sizing both the solar heating system and the backup system.

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3232
Author(s):  
Dorota Chwieduk ◽  
Michał Chwieduk

The paper shows how difficult it is to prove technically that a building really is both low energy and smart, and that all aspects of energy efficiency have been treated equally. Regulations connected to the determination of the energy performance of residential buildings take into account only space and hot water heating energy consumption and define the indices of maximal primary energy consumption, but not energy needs based on the architecture of the building. A single family house designed and constructed as a low energy solar house in Warsaw’s suburbs is considered. Availability of solar energy and its influence on the architecture of the house is analyzed. A specific solar passive architectural concept with solar southern and cold northern buffer spaces incorporated into the interior of the house is presented. Parameters of the building’s structure, construction materials, as well as operation parameters of equipment and heating systems based on active use of solar energy, ground energy (via a heat pump) and waste heat from a ventilation system are described. Results of calculations give values of final and primary energy consumption index levels of 11.58 kWh/m2 and 25.77 kWh/m2, respectively. However, the official methodology for determination of energy performance does not allow for presenting how energy efficient and smart the building really is.


2019 ◽  
Vol 111 ◽  
pp. 04061
Author(s):  
Nick Van Loy ◽  
Griet Verbeeck ◽  
Elke Knapen

In this paper, the spatial use of three underused semi-detached dwellings in Belgium is discussed. The exact user patterns of residents within rooms have been monitored during one week. In the analysis, a distinction has been made between spaces where people move through and have a higher metabolic rate and places where residents stay or sit for a longer time. The analysis shows that residents use some of the rooms only partially and others only for circulation. Furthermore, residents stay only at particular places in the room for a longer period of time. These zones or places are linked to the common activities. Nowadays, most dwellings are heated by a single-zone heating system that heats multiple rooms completely at the same time. However, the spatial use of residents not only shows that particular places in a room are used, but also that they are used at different times. This research illustrates the potential of spatial use patterns for the development of heating systems that are better adapted to the effective spatial use, the activity patterns and corresponding required temperature in residential buildings. This could result in a lower overall ambient temperature and an improved energy efficiency of the building.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2538
Author(s):  
Praveen K. Cheekatamarla

Electrical and thermal loads of residential buildings present a unique opportunity for onsite power generation, and concomitant thermal energy generation, storage, and utilization, to decrease primary energy consumption and carbon dioxide intensity. This approach also improves resiliency and ability to address peak load burden effectively. Demand response programs and grid-interactive buildings are also essential to meet the energy needs of the 21st century while addressing climate impact. Given the significance of the scale of building energy consumption, this study investigates how cogeneration systems influence the primary energy consumption and carbon footprint in residential buildings. The impact of onsite power generation capacity, its electrical and thermal efficiency, and its cost, on total primary energy consumption, equivalent carbon dioxide emissions, operating expenditure, and, most importantly, thermal and electrical energy balance, is presented. The conditions at which a cogeneration approach loses its advantage as an energy efficient residential resource are identified as a function of electrical grid’s carbon footprint and primary energy efficiency. Compared to a heat pump heating system with a coefficient of performance (COP) of three, a 0.5 kW cogeneration system with 40% electrical efficiency is shown to lose its environmental benefit if the electrical grid’s carbon dioxide intensity falls below 0.4 kg CO2 per kWh electricity.


2018 ◽  
Vol 882 ◽  
pp. 215-220
Author(s):  
Matthias Koppmann ◽  
Raphael Lechner ◽  
Tom Goßner ◽  
Markus Brautsch

Process cooling and air conditioning are becoming increasingly important in the industry. Refrigeration is still mostly accomplished with compression chillers, although alternative technologies are available on the market that can be more efficient for specific applications. Within the scope of the project “EffiCool” a technology toolbox is currently being developed, which is intended to assist industrials users in selecting energy efficient and eco-friendly cooling solutions. In order to assess different refrigeration options a consistent methodology was developed. The refrigeration technologies are assessed regarding their efficiency, CO2-emissions and primary energy consumption. For CCHP systems an exergetic allocation method was implemented. Two scenarios with A) a compression chiller and B) an absorption chiller coupled to a natural gas CHP system were calculated exemplarily, showing a greater overall efficiency for the CCHP system, although the individual COP of the chiller is considerably lower.


Author(s):  
Hugo Hens

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.


Electricity demand in India is increasing at a rapid pace because of growth in Economy, urbanization, infrastructure development and the living standard of people. According to the United Nation’s world population prospects (2017), India’s population is 1.34 billion which will go grow further and surpass China by 2025[1]. According to the IMF, the Indian economy is expected to grow by 7.5% in FY19-20 and 7.7% in FY20-21[2]. Increased population and growth in GDP are associated with increased energy demand. India’s primary energy consumption was 754 Mtoe in 2017 and expected to reach 1928 Mtoe in 2040[3]. Major energy demand is from the Industrial sector which was 51% of total primary energy consumption in 2017 and expected to reach 990 Mtoe, by 2040 [3]. Rising energy demand and dependence on coal-based energy generation capacity, leading to the emission of Green House Gases (GHG). Most of India’s Greenhouse gas emissions are from energy sector having 68.7% contribution in overall greenhouse gas emission. Agriculture, Industrial process land-use change and forestry (LUCF), and waste, contributed 6.0%, 3.8% and 1.9% respectively in overall GHG emission in 2014. [4]. Reducing the GHG emission in India is a major challenge in front of the Government as the Government has to maintain sustainable growth with the contribution in mitigating the effect of climate change. Govt. has pledged to Paris Agreement for the reduction in emission intensity of GDP by 33-35% by 2030 below 2005 level [5]. In the reduction of GHG emission, energy efficiency's contribution is estimated at approx. 51% [6]. The industrial sector can contribute most in reducing GHG emission and contributes to nationally determined contribution. Industry consumes 40%-45% of total energy consumption and motor-driven system consumes 70% [7] of total Industrial energy. Most of the energy in Industries are consumed to run the motor for various purposes and consumes a major chunk of energy which can be reduced to a significant level by replacing the standard motor with energy efficient motor. 90% of the motor in Indian industries are IE1 or below IE1 standard [8] and required replacement. By installing the energy efficient motor, the industry can save huge energy, cost and reduce CO2 emission. Observing the opportunity for energy saving by energy efficient motor, this paper aims to analyze how energy efficient motor is capable of reducing energy consumption, and how it can contribute to energy conservation. Methodology adopted in this paper is secondary research, that answers to questions like; why Industry need energy efficient motor, how energy efficient motor can save energy and increases efficiency, cost-benefit analysis of installing energy efficient motor, barriers to the installation of energy efficient motor and solution to those barriers in migration from the standard motor to energy efficient motor in India.


2020 ◽  
Vol 13 (2) ◽  
pp. 90-96
Author(s):  
E.V. Nezhnikova ◽  
◽  
M.V Chernyaev ◽  

The article presents the problems of ensuring energy efficiency of housing construction in the Russian Federation. Unfortunately, for a variety of reasons and, despite the existence of federal and regional legislation, today Russia does not pay due attention to this issue, which leads to an unreasonable increase in electricity consumption both during the creation of residential real estate objects and during their operation. 96 Экономические системы. 2020. № 2 Economic Systems. 2020. No. 2 The relevance of the topic is enhanced by significant energy consumption of residential buildings in use: more than 50% of electrical energy consumption falls on these real estate objects. Therefore, it is no coincidence, but a completely logical trend of the 21st century, that the governments of most countries popularized the idea of designing and building energy-efficient residential buildings. It was established that the improvement of domestic legislation in terms of energy efficiency has greatly improved the regulatory framework for the design and construction of energy-efficient residential real estate.


Author(s):  
Byung Chang Kwag ◽  
Moncef Krarti

A basic principle of well designed greenhouse design emphasizes the utilization of solar energy as much as possible to grow the plants indoors during extreme outdoor climate conditions. Greenhouses can use significant amount of energy due to several factors including poor envelope design, inappropriate maintenance practices, and heavy reliance on fuel-based heating systems. In order to reduce energy consumption in the agricultural industry of Colorado, it is important to design energy efficient greenhouses under Colorado climatic conditions.


2016 ◽  
Vol 37 (2) ◽  
pp. 293-304 ◽  
Author(s):  
Michał Turski ◽  
Robert Sekret

Abstract This paper presents the possibility of reducing the demand for nonrenewable primary energy for buildings using a new conceptual adsorption system of cooling and heating supplied by solar energy. Moreover, the aim of this study is to shorten the payback time of investment in the standard adsorption cooling system through its integration with the heating system. Research has been carried out for an energy-efficient medium-sized single-family building with a floor area of 140 m2 and a heat load of 4.2 kW and cold load of 4.41 kW. It has been shown that the use of an adsorption system of cooling and heating supplied by solar energy decreased the demand for nonrenewable primary energy by about 66% compared to the standard building that meets the current requirements.


2021 ◽  
Vol 13 (9) ◽  
pp. 5266
Author(s):  
Ahmed Abdelrady ◽  
Mohamed Hssan Hassan Abdelhafez ◽  
Ayman Ragab

Building insulation based on nanomaterials is considered one of the most effective means of reducing energy consumption in the hot desert climate. The application of an energy-efficient insulation system can significantly decrease the energy consumed via a building’s air-conditioning system during the summer. Hence, building insulation has become an interesting research topic, especially with regards to the use of insulation based on nanomaterials due to their low U-values. In the present study, the use of nano vacuum insulation panels (VIPs) or polystyrene foam in the walls enabled a significant reduction in the annual energy consumption, a savings of 23% compared to the uninsulated wall in a study in New Aswan City. The application of nanogel glazing to the windows (two layers of clear glass filled with the nanogel) achieved approximately 11% savings in annual energy. This savings, twice that obtained by using double-glazed windows, could be due to the low U-value of nanogel compared to the U-values of argon or air. The embedded nanogel layer between two layers of argon and two layers of single clear glass showed a significant reduction in annual energy consumption, saving 26% compared to the use of a single layer of glass. Moreover, the integration between this window and embedded walls with 50 mm of polystyrene foam exhibited a significant improvement of energy efficiency by 47.6% while presenting the lowest value of simple payback period (SPP). This research provides a way for buildings to be insulated to make them more energy efficient as well as attractive from the economic standpoint.


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