Zero-Energy Building (NEB) Concept - Essay Sample

Introduction

The definition of the ZEB concept guides the worldwide application of photovoltaic in low-income residential buildings. A clear description of ZEB is critical in the operation, design, and evaluation processes. Liu et al. stated that the ZEB application might experience uncertainties and challenges without perfect definition and standardizations. Esbensen and Korsgaard first suggested the defination of ZEB in the 1970s as other energy sources provide heat during winter without any artificial supply. The primary source of power was solar . The definition has gone through tremendous evolution; the EPBD in the European Union require a nearly ZEB to have an extreme performance in low energy consumption from nearby or onsite renewable resources. The Energy Independence and Security Act in the United States defines ZEB as houses that reduce energy consumption without emitting greenhouse gas. In Korea, the Zero-Energy Construction Action Plan for Climate Change describes ZEB as constructions that increase insulation performance by reducing energy consumption and adopting green energy sources to reach self-sufficiency.

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Scholars have also defined the concept, for instance, A NZEB is a high-energy performance building that almost meets the demand of energy by generating it from onsite renewable resources. Wu et al. defined ZEB as houses that generate at least as much energy as they consume annually when accounted for at the building location. Feng et al. simplified using key differences to unify these diverse definitions from different nations. One considers the plug load, and the other focuses on off-site renewable energy. Buildings consume a large share of energy through ventilation, heating, and thermal regulator systems conditions to provide comfort to the residents. The concept of Zero-energy was developed to decrease the excessive consumption of non-renewable power.

Energy Consumption in Residential Buildings

Residential buildings account for a significant portion of energy consumption, and research literature indicates that most of the energy is used for cooling, heating, and ventilating.

Residential energy consumption in an urban area is higher than the rural areas. Approximately 25 percent of the world demanded energy for residential buildings for ventilation, thermal conditioning, and heating. A study conducted by Liu et al. showed that urban residential buildings consume 24 percent of China's total power; heating accounts for the large share, and the results indicated that approximately 40% of the metropolitan area requires heating. The study also showed that energy consumption was directly influenced by energy systems, resident behavior, the envelope structure, climate, maintenance and operation service, resident occupation, and indoor environmental quality. The results concur with a projection conducted by US Energy Information Administration, which indicated that energy consumption is high in commercial and residential buildings. The increase was connected to urban migration and high income.

Wu et al. found that in 2016, residential houses accounted for about 38 percent of the retail electricity sales of electricity. The results concur with a US Energy Information Administration projection, which indicated that energy consumption is high in commercial and residential buildings. The increase was connected to urban migration and high income. The results indicated 42% of technological advances increase energy efficiency, but the level of saving depends on occupant plasticity behavior. Likewise, Amasyali and El-Gohary found that home energy consumption in colon, lighting, and heating depends on occupant behavior patterns. People living in naturally laminated rooms still need artificial lightings because the study found no statistically significant connection between outdoor illumination and non-natural lighting trends. The excessive use of lighting energy is attributed to 20% of the world electricity consumption as the primary source of heat to low-income families. The balance between solar heat and natural light can help save the energy consumed on cooling. Moreover, Amasyali and El-Gohary identified a link between building design and lighting energy consumption, including architectural features, building envelopes, and materials.

Low-Income Residential Buildings

Zhao et al. study indicated that energy performance is consistent in green low-income buildings . However, factors such as technology level, construction type, and building size effect significantly impact energy use. Occupant behavior affects energy consumption inconsistently across years. Low-income buildings consume less power in cooling than heating seasons. Zhao et al. found that zero-energy for low-income residential building help low-income families to save between 3.5% and 9.3% annually. Similarly, results from Kontokosta et al. also concurs that zero-energy for low-income residential buildings reduces expenditure . The investigators found that energy improvements were focused on high-income residential buildings. The burden of energy cost in low-income residential is 7%, while that of the high-income residential buildings is 2%. This indicates that improvements in energy savings systems can help families save up to $1,500 per year.

Passive Design Strategies to Reduce Energy Consumption

Over the last few decades, many studies have paid close attention to buildings design strategies to reduce energy consumption. Passive systems are alternatives that help to decrease the annual consumption of power of a building by 17.2%. They include configuration, window-to-wall ratio (WWR), construction material, insulation for thermal brides, glazing, solar photovoltaic, and a sloped roof. The strategies' effect was assessed, including configuration, WWR, and percentage of the ventilated area on lighting and thermal performance of a building in India. The results showed that insulated walls and mixed-mode ventilation effectively reduce heating, ventilation, air-condition, and cooling (HVAC) loads.

Huang et al. examined several insulation materials in an apartment to determine the optimal thickness and material based on cost and energy consumption reduction. It was revealed that insulated material reduces heating costs by 18%. The effect of multiple parameters, including shading devices, insulation, glazing type, WWR, on the energy performance of two-story houses located in the mountains in Iran showed a reduction of 29 percent. The study of residential buildings in Indonesia showed that natural construction material could reduce the cost of energy. Moreover, the effect of building orientation on the WWR of a residential building was assessed in moderate climates based on g and U values, and the optimal WWR was revealed to lie from 38% and 42%. Energy-saving strategies and solar systems, including shading devices, various construction materials, and double glazing openings, were applied to a building located in Sydney, Australia. The results showed that high thermal mass and solar methods applications effectively decrease energy use. A study by Sun et al. revealed that the most cost effective passive strategy was lighting pies and controls.

Photovoltaic Systems in General

On-site electricity production using solar photovoltaic (PV) systems is currently the most used technology because it is quickly integrated with building facades and roofs. Wu et al. found no significant marginal cost difference between large scale and small scale installation of photovoltaic systems. PV production has been improving with the application of advanced photovoltaic tools. Khakian et al. revealed that producing energy from a building with advanced PV systems saves 350,750 kg of CO2. Albayyaa et al. found that passive solar methods, such as PV modules, can reduce energy consumption.

PV in Residential Building

Studies from experts and investigators have found that PV systems are the most suitable alternative for on-site energy production because they depend solely on sunlight and minimum maintenance costs. The study indicates that most residential buildings rely on solar to reduce the cost of energy. Khakian et al. discovered that PV Panels are not only easy to install, but are effective in exporting to the electricity grid, and found that the size of the most residential building could supply the energy demanded and achieve self-sufficiency. Solar PV installation in residential buildings reduced excessive use of energy remained grid.

Feasibility

Experts have widely focused on energy performance and savings strategies on buildings, for instance, building orientation, shading devices, photovoltaic systems, and window-to-wall ratios. The viability of the photovoltaic modules installed in remote areas was assessed, and the results showed that the 29% energy was saved. The payback period was evaluated at 21.7 years. However, using PV systems as the only source of power requires a large area, reducing the payback period to 82.8 years. The integration and independence of nine types of passive designs strategies were examined, including direct evaporative cooling, passive solar immediate gain high mass, outdoor spaces, ventilation, natural evaporative cooling, shading, passive solar direct gain low mass, double evaporative cooling. The findings showed that passive solar heat gains are the most effective strategy in all seasons. Syed and Abdou showed that electricity production using PV systems provided only 24.7% of the total energy consumed annually, and a combination of measures yielded to 70.7% reduction in energy consumption. The results showed that the energy index decreased from 162.9 to 42.7 kWh/m2/yr. and it indicated that a combination of passive strategies is more feasible than using one measure.

Need for Research

The energy demand has been increasing in the last decades, leading to myriad environmental and economic problems worldwide. Global warming is the primary effect of burning fossil fuels to meet the increased demand. According to Invidiata, buildings are one of the most energy-consuming sectors (over 40%) and release one-third of greenhouse gas (GHG) into the atmosphere. Numerous studies have focused on energy performance and savings strategies on buildings, such as building orientation, shading devices, photovoltaic systems, and window-to-wall ratios. However, these investigations focus on high-income residential buildings that OR have extensive capital for investment. There is little research attention on the viability of zero-energy building strategies in rural and low-income residential buildings. The purpose of the literature review is to examine the studies that demonstrate the viability of the photovoltaic system and passive design strategies toward near-zero energy in low-income residential buildings.