During low winter temperatures, electric resistance heat in aggregate can contribute to peak power events for the electric utility. This study examines the concept of using oversized variable capacity heat pumps to eliminate the need for backup electric heat. Field sites in Orlando, FL served as a basis for the investigation. Results of the field study compare the usage of backup electric heat, annual energy consumption, peak power demand, dehumidification performance, and system cost between the variable capacity and baseline, single speed systems.

This study aims to explore the most appropriate sizing option for a variable capacity heat pump at multiple residential applications. Two variable speed heat pump (VSHP) models were used in simulations of houses located in the mixed-humid and cold climates to determine the impact that sizing has on comfort, energy use and peak power.  A single-speed heat pump sized to the cooling load was used as a reference for each home.  Simulation results indicate up to 10% annual energy savings are achievable by sizing VSHPs to the heating load in cold climates, with decreasing savings in warmer climates.

Electricity consumption per capita has been gradually increasing by 8% annually during the past 10 years in the Kingdom of Saudi Arabia. One of the main reasons for this above-average growth rate is the utilization of low-efficiency electrical home appliances, which is encouraged by the low initial investment and the artificially low energy prices. In 2013, the residential sector consumed nearly 126 terawatt hours, which represents 49% of the country’s electricity consumption. This paper investigates the potential savings in primary energy that can be achieved by switching residential water heating and cooking appliances from electricity to liquefied petroleum gas (LPG).

This paper describes a single-circuit hot gas bypass defrost strategy, similar to those used in commercial refrigeration applications, for a residential heat pump. The hot gas bypass strategy does not require a reversal of the cycle, but instead bypasses some hot gas from the compressor discharge line through some or all of the circuits of the evaporator (outdoor unit) coil to remove frost. Similar defrosting strategies are successfully utilized in large-scale refrigeration systems, such as those used in supermarkets, but these methods are not commonly implemented in smaller systems for the residential or light-commercial markets. A prototype system was developed for investigation consisting of a manifold system that allows hot gas to be bypassed from the compressor discharge line through any or all of the five circuits on the outdoor unit coil.

This paper proposes the conditional demand analysis (CDA) methodology, which is relevant in electric energy consumption by main household facilities and suggests important variables that can affect CDA values, accordingly. Although households, particularly apartments, are considered the main primary energy- and electricity-consuming housing type in Korea, efforts on reducing electricity consumption by households are limited. The usage of energy is mainly focused on primary energy. Considering that many attempts have been made to reduce residential energy consumption, disaggregating total electric energy consumption into specific end-use level such as heating, cooling, ventilating, hot-water supply and lighting, is a very useful method. In general, by obtaining information on the energy consumed by each piece of equipment, we can easily determine the total electric energy consumed.

Plumbing noise is a common complaint in residential settings and difficult to correct after construction since remediation often involves tearing out walls, floors and ceilings. Despite the obvious potential for impact between occupancies, plumbing noise is largely ignored by building code and consequently receives limited priority during design and construction. While appropriate solutions are widely available, successful outcomes require coordination between multiple disciplines and trades in order to maintain cost effectiveness without unacceptable risk. This presentation will emphasize the practical side of plumbing noise control and cover key essentials to help design and construction professionals better avoid plumbing noise problems.

The presentation will discuss the modern construction materials and techniques that lead to good sound isolation in multi-family residential developments. Theoretical, lab and real-world tested sound and impact isolation data will be presented for various construction elements and partition configurations. Examples of construction challenges that result in less than optimal sound isolation also will be presented.

This session provides an in-depth look at AHRI 275: Application of Outdoor Unitary Equipment A-Weighted Sound Power Ratings.  This looks at sound propagation from rooftop and ground mounted units, the effectiveness and installation of noise barriers, and issues that arise with wall installations.  This session provides a summary for design-build engineers, contractors, and mechanical engineers that need to do basic radiated sound estimates.

Mechanical ventilation with heat recovery (MVHR) systems, provide a controllable method of ventilating dwellings while delivering energy savings. They are particularly useful for ventilating homes in noisy areas or high-rise buildings where open windows are not workable. However, they can be a source of noise, particularly if they are not located and installed carefully. Drawing on a range of large residential projects, laboratory testing and on-site measurements, this session will present the acoustic advantages and pitfalls with their use, and will give real advice to engineers, architects and contractors on how to specify and configure these systems for quiet operation.

Residential energy codes have rapidly advanced, and many builders offer “Net Zero Energy” or "Zero Energy Ready" homes.  But as homes get more efficient, risks of design and installation defects increase.  Increased insulation can elevate moisture risk inside wall assemblies. Increased air tightness can lead to IAQ problems without proper ventilation.  Lower envelope loads reduces HVAC system air flow and can lead to poor comfort control. Energy efficient homes must also be high performance homes. This presentation will describe innovative solutions for high performance homes and retrofits under U.S. DOE’s Building America program that minimize risks and maximize comfort.

The energy-efficiency levels of new homes built in the U.S. has improved significantly in the past decade with developments in building science and improved construction practices according to the United States Department of Energy (DOE). The improvement in the building thermal envelope and several other factors can cause the house to operate intermittently at a negative pressure.  Natural gas appliances can vent properly at a negative pressure, but some appliances only operate within limits.  This presentation explores the operating limits and provides data on performance from recent laboratory testing of appliances under depressurized conditions.

Part of the energy performance increase in new homes and homes being retrofitted is due to reducing the air leakage through the building envelope. However, a high performance home should still have good indoor air quality and therefore requires ventilation to remove pollutants from individual sources, such as in kitchens and bathrooms, generated by occupants and their activities and from building materials and furnishings. This seminar will discuss how to apply ASHRAE 62.2 in high performance homes and show how to improve upon the basics required in the standard through selection of different ventilation approaches and equipment.

This presentation will begin by eliciting audience feedback about their experience with and impressions of biomass hydronic heating systems. After this, a quick survey of the most common biomass feedstocks and system types will familiarize the audience with those they are likely to encounter. Then we lead in to a discussion of the essential differences between biomass and fossil fuels in terms of performance, especially turn down ratios, ash and moisture content, advances in emissions control, and storage and supply issues.

This presentation will provide a look at some of the most important design issues that come to the fore when implementing a hydronic biomass boiler system. Segueing from fuel supply and storage considerations (the topic of the first part of the workshop), we will proceed to discuss boiler sizing and thermal storage in biomass systems. Advantages of multiple-boiler systems for varying load profiles will also be discussed. When these issues are understood, biomass hydronic systems are at their most efficient and provide an excellent alternative to fossil fuels or other renewable energy sources such as solar thermal for heating purposes.

As more distributed energy resources are installed, the electric grid needs to become more nimble to support and take advantage of these renewable but intermittent sources of energy.  Many smaller loads could be controlled to provide stability to the grid and allow more clean sources of energy to be added to the grid, but the extent to which specific devices can help the grid is not yet known. The National Renewable Energy Laboratory and the Electric Power Research Institute are characterizing the grid services of five connected devices: PV inverter, electric vehicle charging station, community-scale battery, pool pump, and thermostat.  

The use of heat pump water heaters (HPWH) in the residential sector will provide theoretical energy

savings of up to 63% per water heater over a typical electric resistance water heater (ERWH). However,

to a utility, energy-efficient technologies are the most desirable when they provide grid stability and

control benefits through demand-response (DR) capabilities. This presentation will discuss the DR

performance of various HPWHs compared to an ERWH as demonstrated by experiments using the side-

by-side PNNL Lab Homes. Experiments included testing each water heater for two typical

types of DR events: peak curtailments due to oversupply, and balancing reserves.

One of the benefits of the smart grid is the ability to leverage grid-connected, demand-response (DR) ready appliances to help consumers better manage their energy costs and electric utilities better manage their power distribution. This presentation will examine the field performance of DR ready refrigerators, clothes washers, and dishwashers in three blocks of homes over a period of nearly two years, and compare their performance with a series of DR testing conducted in the laboratory prior to their field deployment.

The single-family residential building stock in California is dominated by gas-fired storage water heaters. This is a result of the building energy efficieny code. For decades the water heater energy consumption calculated in the budget compliance tools has made it very hard to justify using an electric resistance water heater. As a result very few electric water heaters have been installed. The compliance tools were written in a way that poorly calculates the hot water load. Furthermore the calculated time of energy use by water heaters does not account for the buffering effect of a storage tank. An important part of the budget calculation uses a time dependent valuation of electrical generation to capture the societal costs of using electricity for every hour of a typical year. This has meant that the actual effects of the time difference between the hot water use and the energy consumption of electric storage water heaters are not being evaluated properly. The combined effect of these oversights has inadvertently effectively blocked the adoption of heat pump water heaters in new construction in California. This presents a major obstacle for reaching the state's net-zero energy and greenhouse gas emission targets. This paper describes the way the building energy efficiency code currently calculates the water heater energy budget. Problems in the calculation procedure are explained. Our knowledge about residential hot water systems has increased greatly in recent years. These research efforts have significantly improved our ability to characterize these systems. Revisions to the building code calculations are suggested based on this increased knowledge. An enhanced hot water load calculator has recently been adopted by RESNET. Detailed field studies over the past several years of residential hot water draw patterns provide a source for more realistic draw schedules to use in the calculations. An open source water heat simulation model developed for utility incentive programs in the Northwest could be adapted to calculate the amount and timing of energy use. The role of demand response controls to reduce the impact of electric heat pump water heaters on the grid are also discussed.

The purpose of this paper is to study the energy impact of operating a HPWH in the basement of an R-2000 equivalent house, i.e. the Canadian Centre for Housing Technology (CCHT) twin house test facility, located in Ottawa Canada. We included four key parameters in the study: Did the operation of the HPWH have any adverse impacts on the basement air temperature? Was the HPWH operating more efficiently than the baseline water heaters? What if any were the impacts on energy consumption during the heating and cooling seasons and were there energy cost savings during the Heating and Cooling Seasons?

In the effort to achieve net-zero operation of residential buildings, advanced water heating technologies are vitally important.  Solar thermal is the most cost and energy efficient, renewable energy alternative for water heating, but the use of electric resistance as the backup to solar thermal may no longer be the most suitable option. This paper explores the year-long performance of a 189 liter (50 gallon) heat pump water heater (HPWH) serving as an auxiliary unit to an active indirect solar thermal water heater with a 303 liter (80 gallon) storage tank in a net-zero energy test home at the National Institute of Standards and Technology, Gaithersburg campus.

Approximately half of water heaters sold in the U.S. and Canada for residential applications are natural gas fired storage water heaters, and for these products the maximum steady state thermal efficiency of available products is approximately 96%, with transient rated efficiencies much lower.  To move beyond the thermal efficiency limits of standard condensing-efficiency residential gas water heating equipment, this paper describes an effort to develop an economic gas-fired ammonia-water absorption heat pump deployed as a packaged storage water heater.

This talk discusses major findings from three in-depth residential occupant studies that were conducted over the past two years. The objective of the studies was to shed light on the complexities of occupant behavior by performing long-term monitoring with interviews and surveys. The first study looked at the effect of billing schemes on occupant control of indoor temperature. The second study examined window shade use and found patterns are significantly different than in office buildings, but that occupants seldom move their shades. The third study examined the comfort and purchase decisions of modern, highly-glazed apartment buildings.

In rural China, household heating using solid fuel significantly contributes to both indoor and regional emissions of pollutants such as carbon monoxide and fine particulate matter (PM_2.5). This study presents the first results from an intervention study currently conducted in Beijing suburb, China. The purpose of this particular effort is to quantify the effectiveness of using a split-type, low-temperature air source heat pump as an alternative way of clean heating in rural households. Several “representative” occupant control modes were summarized, all based on residents’ own use pattern without much instruction.

Improving energy efficiency behaviors requires the consideration of technology improvement and human factors. While a growing number of recent studies have focused on the importance of environmental behaviors, little attention has been paid to a comprehensive set of social-psychological factors associated with occupants’ energy conservation and demand response behaviors.  Moreover, appliances and facilities are often shared among coworkers, which inhibit the development of a sense of individual responsibility. Gaining a deeper understanding of the social-psychological factors influencing energy efficiency behaviors in both public or residential buildings is especially relevant for policy and academic conversations about mitigating global climate change.

Previous research studies show that occupancy behavior accounts for about 30% of the variance in overall heating consumption and 50% in cooling consumption in residential buildings. Overall energy savings of 10–20% due to simple behavioral adjustments are a reasonable expectation. Unfortunately, there are few studies have focused on the specific case of behavior in low-income housing, where unique individual energy behavior, demographic and socio-economic factors come into play. This presentation investigates occupancy behavioral energy usage in low-income families through real-time measurement.  The behavioral aspects are presented in terms of thermostat schedules, occupancy presence and major appliance usage.

A net-zero energy (NZE) residential test facility is used to evaluate options for achieving NZE performance on a home similar in size, aesthetics, and amenities to those in the surrounding communities while meeting the average electricity and water use needs of a family of four.  The facility incorporates renewable energy and energy efficient technologies, including a heat recovery ventilator sized to meet ASHRAE Standard 62.2-2010 ventilation requirements, because ventilation is a significant portion of the energy requirement in a NZE home.  This presentation will discuss the operation of the HRV and its impact on the indoor air quality and energy use.

Net zero energy (NZE) homes require additional investments in improving energy efficiency and adding rooftop PV.  It can be challenging to determine the most cost effective way to reach NZE because it depends on climate, energy costs and relative costs of energy efficiency and PV technology options. BEopt software can be used to evaluate residential building designs, identifying cost-optimal performance packages at various levels of whole-house energy savings. This presentation will provide a brief overview of BEopt capabilities along with several case studies of NZE homes designed and built using information from BEopt.

As net zero energy (NZE) construction gains momentum, so does the number of stakeholders who believe electrification is the best way to achieve NZE performance.  However, natural gas provides a clean, affordable and domestic energy option for NZE homes that is often overlooked when stakeholders think only in terms of site energy performance.  This presentation will focus on California’s ambitious NZE goals, describe how NZE is calculated in California, and showcase the societal benefits of including high efficiency natural gas direct use as a viable alternative to electric technology options for NZE homes in California.