Decarbonization pathways for the residential sector in the United States

Residential GHG emissions in the United States are driven in part by a housing stock where on-site fossil combustion is common, home sizes are large by international standards, energy efficiency potential is large, and electricity generation in many regions is GHG-intensive. In this analysis we assess decarbonization pathways for the United States residential sector to 2060, through 108 scenarios describing housing stock evolution, new housing characteristics, renovation levels, and clean electricity. The lowest emission scenarios rely on very rapid decarbonization of electricity supply alongside extensive renovations to existing homes—focused on improving thermal envelopes and heat pump electrification of heating. Reducing the size, increasing the multifamily share, and increasing the electrification of new homes provide further emission cuts, and combining all strategies enables emissions reductions of 91% between 2020 and 2050. Construction becomes the main source of emissions in the most ambitious scenarios, motivating increased attention on reducing embodied emissions.

Assessing the Energy Efficiency Potential of Recycled Materials with Construction and Demolition Waste: A Spanish Case Study

Buildings are responsible for 40% of the overall final energy consumption in the European Union. On the other hand, the construction, energy, and industry sectors generate around 50% of the waste produced in Europe, out of which a third part is construction and demolition waste (CDW). In recent years, many research works have been carried out to analyze the viability of incorporating waste, especially CDW, as a substitute for traditional raw materials with great environmental impact. However, most of the studies found cover only the mechanical characterization of the compound, and there are very few that analyze these materials in specific building applications. This research work evaluates the energy efficiency potential of recycled materials with CDW. After an exhaustive analysis of the main existing recycled materials, an energetic evaluation of several construction solutions is carried out, as well as a comparison with traditional solutions. The findings show that the incorporation of recycled materials in several building construction elements is a success, since it not only reduces the consumption of raw materials, but also reduces the energy consumption of the building. Energy savings using recycled materials can range from 8% in a warm region (such as Seville) up to 13% in cold regions (such as Soria), which are greater in heating than in cooling.

Environmental assessment of entropy control in flight process

Purpose This study aims to examine exergy efficiency of engines and entropy performances at the flight process. In addition, the improvements that can be achieved in the system with the effective parametric controls of the engine have been evaluated in terms of both efficiency and entropy in the system. Design/methodology/approach According to the flight characteristics of the engine, the altitude-dependent irreversibilities and their environmental effects were discussed with two developed indicators, energy performance indicator (EPI) and sustainability indicator (SI). Findings According to the results of both indicators, the energy efficiency potential of the engine during the flight process was found to be 15.02%, while the fuel-based efficiency potential was 18.84%. Research limitations/implications It is limited by the flight process of a Turboprop engine. Practical implications The management tools and criteria of entropy are very difficult model studies. The study offers an evaluable approach based on two basic criteria developed for engines. Social implications In monitoring and review of entropy management related to fossil fuel technologies, key indicators developed can be used as benchmarks for managing emission sources Originality/value The two basic indicators developed can be used as monitoring measurement tools of sustainable energy and environmental performances for engines and applications.

Passive Solar and Conventional Housing Design: A Comparative Study of Daylighting Energy Efficiency Potential

The increasing energy consumption and its resultant CO2 emission in the built environment have revolutionized the housing design. Buildings are strategically designed to harness ambient weather factors for indoor space thermal conditioning and lighting. A comparison of the daylighting and potential environmental mitigations due to the lighting energy consumption in a passive solar and the conventional house was the aim of this study. Both houses used as a case study are in Alice, Eastern Cape in South Africa. The indoor illuminance of the homes was monitored using Li-Cor 210R photometric sensors. Between 07 h00 to 16 h30, the passive solar house’s average daylighting was 217 lux and 56 lux in the conventional house on a clear sky. Under the same sky condition, there was 47% lighting energy saving. This reduces the amount of coal usage by 1.97 kg, 3.53 kg of CO2, 14.80 g of NO2, and 4.76 L of water. In contrast, no energy savings were achieved in the conventional home. The equivalent environmental impacts due to 4.20 kg of coal usage were 7.52 kg of CO2, 31.52 g of NO2 emissions, and 10.14 L of water usage. From the findings, daylight harvest through passive solar design shows the potential of energy savings and environmental mitigation measures in the housing sector.

Green Retrofit Energy Efficiency Potential on Existing Building Envelope for Residential and Non-Residential Building

The chapter deals with the green energetic consideration of today's building envelopes for residential and non-residential buildings. It investigates the energetic effects the envelopes have on energy efficiency, energy consumption, material use, sustainable use of resources, lifetime considerations, economic and ecological impact. Today's it is estimated that approximately 30% of the annual primary energy demand for residential and non-residential buildings is needed. Energy resources for heat, electricity, air conditioning and cooling purposes, fossil fuels in form of gas and liquid are predominantly used.

Green Retrofit Energy Efficiency Potential on Existing Building Envelope for Residential and Non-Residential Building

The chapter deals with the green energetic consideration of today's building envelopes for residential and non-residential buildings. It investigates the energetic effects the envelopes have on energy efficiency, energy consumption, material use, sustainable use of resources, lifetime considerations, economic and ecological impact. Today's it is estimated that approximately 30% of the annual primary energy demand for residential and non-residential buildings is needed. Energy resources for heat, electricity, air conditioning and cooling purposes, fossil fuels in form of gas and liquid are predominantly used.

Application of AHP and GRA methods in energy efficiency potential’s assessment of envelopes from natural materials

The best choice of energy efficient envelope from variety of available materials is still the challenge. Therefore, the attempt of thermal performance multi-criteria evaluation of some building materials of natural origin for energy-efficient envelopes is conducted in present paper. Such types of walls from natural energy-efficient materials are considered in comparison assessment: hempcrete, adobe, strawbale panel, earthbag, cordwood, SIP (plywood+ecofiber), hempcrete+straw and energy efficient block. The influence of thermal inertia time, internal areal heat capacity, as well dimensionless index of thermal inertia D, the total thermal resistance of the walls Rtot-value, mass of the wall assembly and its cost have been taken into consideration as important influence factors. The multi-criteria numerical assessment of envelope’s energy efficiency potential was performed by two popular methods – Analytic Hierarchy Process (AHP) as the subjective weighting method and Grey Relation Analysis (GRA) as the objective weighting method. Both of methods allow to arrange the alternatives and could be applied as decision support tools in decision making (DM) process of choosing the best alternative in terms of multi-criteria assessment. For more objective analysis, by taking into account the variety of physical and physical-mechanical parameters of the wall assembly material, the concept of generalized index of the envelope energy efficiency potential is proposed. Conducted research has shown that the best envelope type in terms of of generalized index of energy efficiency potential has the hempcrete wall and hemcrete+straw wall, almost three times smaller has the wall of the earthbags. The walls from adobe, cordwood and strawbale panels have practically the equal value of generalized index of energy efficiency potential. It could be observed that AHP method shown more inhomogeneous results, than GRA. The possible reason for that is the difference in evaluation attitude in techniques - AHP is considered as the subjective method with pairwise comparison matrixes, while GRA is objective method of comparison.