Net Zero Energy Homes Research Articles

Editorial

In response to growing global warming issues and the constant increase of energy prices, housebuilders and housing manufacturers today are becoming more responsive to the delivery of net zero energy and carbon dioxide (CO2) emission sustainable homes than ever. Within this context, the sustainability may embrace housing economy and adequacy beyond the legitimacy in which the quality barely coincides with individuals' dynamic various needs, desires and expectations. Nevertheless, the industry's business operation tends to follow routines and the close system mode of operation often hinders the enterprises from adopting unfamiliar innovations which may be inevitable in realising the delivery and operation of socially, economically and environmentally sustainable homes.

An information driven hybrid evolutionary algorithm for optimal design of a Net Zero Energy House

Building Performance Simulation (BPS) is a powerful tool to estimate and reduce building energy consumption at the design stage. However, the true potential of BPS remains unrealized if trial and error simulation methods are practiced to identify combinations of parameters to reduce energy use of design alternatives. Optimization algorithms coupled with BPS is a process-orientated tool which identifies optimal building configurations using conflicting performance indicators. However, the application of optimization approaches to building design is not common practice due to time and computation requirements. This paper proposes a hybrid evolutionary algorithm which uses information gained during previous simulations to expedite and improve algorithm convergence using targeted deterministic searches. This technique is applied to a net-zero energy home case study to optimize trade-offs in passive solar gains and active solar generation using a cost constraint.

Optimization by Discomfort Minimization for Designing a Comfortable Net Zero Energy Building in the Mediterranean Climate

The energy design of a building is a multivariable problem, which can accept different sets of solutions. In this paper an integrated energy design process is proposed to support designers in identifying the most suitable set of passive solutions to guarantee a comfortable indoor environment and hence to minimize its energy needs for space conditioning. The proposed design process uses EnergyPlus as energy simulation engine, guided by GenOpt via some code written by the authors. The optimization aims at minimizing two seasonal long-term discomfort indices (based on the ASHRAE Adaptive comfort model) through the Particle swarm optimization algorithm. We test here the proposed process in a case study where we identify the most suitable envelope components and passive strategies for the design of a single-family net zero energy home located in the Mediterranean climate. The building is now actually under construction. It should be noted, however, that the modeling and the optimization approach outlined in this paper can be applied to any residential or commercial building prototype.

CRITICAL SUCCESS FACTORS TO LIMIT CONSTRUCTABILITY ISSUES ON A NET-ZERO ENERGY HOME

The objective of this study was to identify the critical success factors (CSFs) to limit constructability issues on a net-zero energy home, in an effort to enhance sustainability and increase competitiveness in the residential construction industry. An extensive literature review was conducted to determine common constructability issues and to compile success factors identified previously by other researchers for traditional home construction. The CSFs were then narrowed to a group of thirteen CSFs unique to net-zero energy home construction. This framework of net-zero energy CSFs was supported by a case study of a net-zero energy home under construction in Pittsburgh, Pennsylvania. Through the use of observational research on this home, the importance of each CSF was defined, and their contributions to a net-zero energy home was discussed based on evidence from the case study. CSFs and constructability issues identified in this research will assist the residential construction sector's continued effort to reduce energy use, enhance conservation, and promote sustainability through the support of net-zero energy residential construction. CSFs will promote sustainability by increasing the ease and efficiency of the design and construction of net zero energy homes which will in return make the homes more cost efficient to build and an affordable option for home buyers.

Towards zero energy homes down under

Abstract The concept of net zero energy and zero emission home has been a goal for those involved in the sustainable building industry. It is now becoming a reality in many parts of the world with an integrated approach of passive design, energy efficient appliances and local renewable generation. The paper describes the activities in Australia focussing on reducing energy use from the housing sector. It describes the regulatory approach of energy performance for housing which involves developing a house energy rating tool covering the building envelope as well as major energy consuming appliances. It also describes the implementation process which comprises gradually more stringent regulations coupled with financial inducements. The paper describes a world leading new Australian housing development where net zero energy homes are being built and enjoyed. It tells the story of how this outcome is being achieved starting with the planning process and developing environmental guidelines. The paper describes the innovations being used in order to achieve net zero energy homes and reports on energy monitoring results and feedback from householders.

Designing net-zero energy buildings for the future climate, not for the past

Net-zero energy buildings (NZEBs) are expected to play an important role in fighting climate change and reducing the energy use of the built environment. But even if the best design practices are widely adopted and implemented, this will only mitigate global warming. It is too late to prevent it. Yet buildings – including net-zero energy buildings – are often designed using historical data representing the average climate between 1961 and 1990, or between 1976 and 2005 at best.This paper investigates the use of the downscaling method known as “morphing”, proposed by Belcher et al. (2005), to generate weather data files. The impact of using these weather files on the energy performance of an actual NZEB is then assessed. Morphing is applied to typical “horizon years” representative of future climate and also on a month-by-month and year-by-year basis using raw data from a selected GCM. A 50-year series of hourly weather data is obtained and analyzed for two different locations, Montréal (QC) and Massena (NY). The data are then used to simulate the performance of a net-zero energy home as it was designed using historical data. The results show that the building misses the net-zero energy target for most years. The year-to-year variability of the total energy use is relatively small but the impact on the energy excess or shortage in relation to the net-zero target is significant. climate-sensitive buildings such as NZEBs should always be designed using multi-year simulations with weather data that take climate change into account.

Economic feasibility of energy efficiency measures in residential buildings

A study has been performed to develop cost benefit data to be used by a local electric utility in defining a rebate program to encourage energy efficient construction in the Desert Southwest region of the USA. Several potential efficiency upgrades for production homes in the region were identified and an evaluation of each building component was performed using building energy simulation software. A model home developed in Las Vegas was used to calibrate the numerical model and was considered as a basis for further study. The validated building models were then used to predict the annual energy savings and payback periods for various upgrades. In all cases, comparisons were made to code-built houses with the same general overall characteristics. Useful life of most of these upgrades far exceeds their payback periods. It is found that a typical house, with the cost-effective upgrades installed, consumed 42.5% less annual energy compared to a home built to code. A 3.19 kWp PV system installed on the south-facing roof of the home can generate 5982 kWh annually, making it a net-zero (electrical) energy home. PV systems in Las Vegas have encouraging benefit cost ratios when federal and state rebates are considered.

<p>Toward a Zero Energy Home: Applying Swiss Building Practices/Attitudes to U.S. Residential Construction</p>

This project evaluated typical U.S. and Swiss homes to identify construction practices that are most energy efficient and have economic payback. A net zero energy home (ZEH) produces as much energy as is consumed in it over time. Students in a College of Technology in a Midwest Indiana State University and a technical University in Switzerland resulted in developing models of homes that combined U.S. and Swiss standards. The project was completed in two phases: during the first phase of this project, construction costs, energy use, and economic payback was calculated for six homes that were designed using both Swiss and U.S. standards. During the second phase of the project, cultural norms that influence energy use were explored. A survey was used to compare U.S. and Swiss college students’ lifestyles and energy habits. All homes had the same basic size and layout, but some used construction practices typical for the United States and others were designed according to Swiss guidelines for residential construction. The results of the study showed that a Swiss-style low-energy home is not cost effective for the Midwestern United States if energy costs remain low, but it could become attractive if energy rates escalate significantly. It was also recognized that technology by itself will not minimize energy consumption, a result of the second part of the project that explored cultural norms that influence energy use. From the survey of both U.S. and Swiss college students’ lifestyles and energy habits, it was revealed with a high level of confidence that Swiss students are more energy conscious than their U.S. counterparts.

Net Zero Energy Homes: An Evaluation of Two Homes in the Northeastern United States

This paper will discuss two Net Zero Energy homes in the United States. The aim is to discuss the differences and similarities in the construction type, energy use, active and renewable systems of the two homes. While each of the homes is designed to achieve net zero site energy use, the design and systems are very different. Furthermore, the measure that is used to qualify a home as net zero energy does not account for the full scope of work on each home. It is suggested that a new set of metrics be developed to allow for a more robust understanding of net zero energy buildings, one that integrates passive design strategies, occupant health and comfort, and durability. The objective is to facilitate a broader understanding of efficient and sustainable residential design. This understanding is critical to bringing Net Zero Energy Buildings to the public.

Net Zero-Energy Home Design Strategies Learned From Canadian Experience

In response to the growing demand for zero-energy housing, today's home needs not only to be energy-efficient, but also to provide part of its own energy requirements. The energy efficiency may be improved by applying high thermal performance building envelope and passive energy and environmental systems to housing. Micro-power can be generated through the use of renewable energy technologies. This paper is aimed at providing a comprehensive guideline on the design techniques and approaches to the delivery of net zero-energy healthy housing in view of the ÉcoTerra house, which won the Canadian federal government's EQuilibrium sustainable housing competition. The house was built in Eastman in the province of Quebec and it is currently open to the general public in order to sharpen the consumers' awareness of commercially available net zero-energy healthy housing today.