Residential Ground Research Articles

Evaluation of decrease in stiffness of residential ground using unsteady changes in the spectrum of ground surface acceleration records

Evaluation of decrease in stiffness of residential ground using unsteady changes in the spectrum of ground surface acceleration records

A variable speed water-to-water heat pump model used for ground-source applications

The main objective of this study is to model variable speed water-to-water heat pumps ( VSHP ) and to examine the impact of the operation of such devices on ground heat exchanger sizing and energy consumption when they are used in ground-source applications. In the first part of the paper, a complete physics-based steady-state model of a variable-speed water-to-water heat pump is briefly presented. A performance map approach is also used by modifying an existing TRNSYS variable speed heat pump model to provide a minimum speed of operation and a better representation at part load. Simulation results over a heating season on a residential ground source VSHP indicate that the energy coverage (i.e., percentage of annual heat supplied by the heat pump) increases at a faster rate than the effect coverage (i.e., percentage of peak building heat supplied by the heat pump) for a small value of the effect coverage. For example, for effect coverage of 60%, the energy coverage is ∼ 93%. It is also shown that the normalized length of the ground heat exchanger varies linearly up to effect coverage of 60% where it is equal to 75% of the value encountered for effect coverage of 100%.

Manganese relative oral bioavailability in electric arc furnace steel slag is influenced by high iron content and low bioaccessibility

Electric arc furnace (EAF) slag is a rock-like aggregate produced with carbon steel and used for construction, including residential ground cover. It is enriched with manganese (Mn) and other metals, including iron (Fe), but because metals are bound in mineral matrices, in vitro bioaccessibility (BA) is limited. We conducted a relative bioavailability (RBA) study using F344 rats to assess Mn RBA from EAF slag ingestion, compared with Mn in diet. Mn and Fe were measured in liver, and Mn in lung and striatum, the target tissue of the brain. Mn levels in each tissue were fit by dose-to-tissue concentration (D-TC) curves. The D-TC relationship was the most highly significant for the linear model using liver Mn, and the RBA was 48%. The D-TC relationship in lung showed a positive slope for chow, but that for EAF slag was slightly negative, and the RBA was 14%. In comparison, the striatum D-TC remained relatively constant, supporting that homeostasis was maintained. Increased Fe was observed in the liver of EAF slag-dosed groups, suggesting that Mn absorption was inhibited by the high Fe content of slag. Lung and striatum D-TC curves demonstrated that systemic delivery of Mn from EAF slag ingestion is limited and support an RBA of 14% for risk assessment. Although Mn levels in slag are elevated compared with health-based screening guidelines, this study supports that incidental ingestion of Mn in EAF slag is unlikely to pose a neurotoxicity hazard due to homeostatic controls, low BA, and high Fe content.

Groundwater in collapsing residential ground

Groundwater in collapsing residential ground

Clustering based on dynamic time warping to extract typical daily patterns from long-term operation data of a ground source heat pump system

While clustering has been commonly used to profile the building electricity consumption data, its application to HVAC system data is relatively less. Based on the operation data of a residential ground source heat pump (GSHP) system, a pre-processing procedure was set up, including acquisition, cleaning, missing-data fill-in, and standardization. Then hierarchical clustering was used, based on the dynamic time warping (DTW) distance calculation method. A new index, the sum of squares of errors based on DTW, was used to determine the best cluster number. The patterns were extracted based on clustering results.The heat exchange on the user-side during one cooling season was processed as a case study. We obtained 5 valid clusters and extracted patterns from each. For the studied case, the result based on the DTW method yields a better homogeneity compared to the Euclidean method. The method is then applied to a five-year operation data, where 9 and 6 patterns were obtained for the cooling and heating seasons, respectively. They mainly differed in shape, and the cooling patterns fluctuate more. Overall, clustering and pattern extraction can reduce the data dimension, and provide a data-driven view of how the system supplies the cooling and heating.

Utilization of on-grid photovoltaic panels to offset electricity consumption of a residential ground source heat pump

Ground source heat pump (GSHP) system is an efficient solution to mitigate energy consumption and environmental emissions in the building sector. Although the GSHP system is categorized among renewable energy technologies, considering the fact that the system's power demand is usually provided by fossil fuel resources, it may not fully meet this classification. One way to offset the GSHP's electricity consumption in a renewable approach is the use of photovoltaic (PV) panels. This paper aims to study the feasibility of a hybrid PV-GSHP system for a residential building in Tehran, Iran. To that end, a numerical model is developed to explore the GSHP system's performance over a 20-year design life, taking several borehole lengths into account. Moreover, the PV modules are simulated by EnergyPlus software. A life cycle cost analysis is also performed to assess the economic viability and optimal design of the PV-GSHP system. The results illustrate that using four PV modules can best cover the system's electricity consumption and the discounted payback period is less than four years. Furthermore, an environmental evaluation reveals that the PV-GSHP system can save 29.2 t of carbon dioxide emissions over the 20-year period compared to the GSHP system.

Hill Slope Failure During The Development Of Infrastructure Projects In Himalaya: Case Study of Udhampur- Ramban National Highway, Jammu and Kashmir, India

Himalaya is youngest tectonic Active Mountain and northern boundary of India. Various infrastructure projects are under develop in Himalayan region for the better connectivity of peoples and national security of border line. Widening of 295 km National Highway-44 in Jammu and Kashmir is an important developmental project. The highway passes through Outer Himalayan and Higher Himalayan sequences of rocks and is frequently affected by landslides at various places. The paper deals with 43 km Udhampur-Chenani and Nashri- Ramban section of the highway within sedimentary and metamorphic rock sequence. The area is prone to landslides on account of fragile geological, topographic and hydrological conditions. The study area has high rainfall intensity and numerous old landslides zones. During the project feasibility stage, project authority has identified the landslide prone area and suggested precautionary measures but during the construction work various unpredicted landslide and ground sinking events happened which given trouble in project construction cost and project completion time. In this paper, the challenges faced due to landslide and ground failure as failure of old slide adjutant to road construction, agriculture and residential ground failure at higher altitude due to road construction, collapse of high tension towers in cut slopes; its impact on construction activities; are discussed with mitigation measures for unidentified landslide related challenges.

Life cycle analysis (LCA) of residential ground source heat pump systems: A comparative analysis of energy efficiency in New Jersey

Developing clean energy policy supported by science-based research is essential for mitigating the hazards and risks associated with climate change. This study aims to explore ground source heat pump (GSHP) systems, an underutilized energy efficiency technology, as a means to promote emission reductions in the buildings sector. GSHP systems have the capacity to decrease the environmental impact of building space heating and cooling needs through fossil fuel displacement and higher energy efficiencies than baseline technologies. Although the benefits and engineering applications of this technology are established, it has not been adopted at scale, thus limiting potential emission reductions. Furthermore, energy economics can vary significantly across geographies which makes quantifying benefits of mitigation action challenging in regions with diverse electricity generator types and building heating fuels. This study uses life cycle analysis (LCA) to evaluate mid- and long-term sustainability metric impacts of GSHP systems operating in New Jersey, US, to assess the technology’s effectiveness while operating within the state’s electricity generating fuel mix. Results show that the state is a suitable location for residential GSHP systems, and that an electricity generation fuel mix with increased use of renewable energy sources would enhance the technology’s efficiency and decrease associated emissions even further. In addition, we compared GSHP technology to that of other common space heating/cooling methods and found that use of GSHP systems in conjunction with electric-based heating/cooling provides a substantial improvement in terms of environmental emissions. When compared to oil and gas-based heating, GSHP systems provided some improvement on mid-point impact factors and considerable improvement on end-point impact factors, most notably the economic improvement associated with decreasing dependence on fossil fuels. These findings suggest that GSHP systems should be considered for reducing emissions and end-use energy consumption and support new clean energy policies in the state.

Performance assessment and techno-economic optimization of ground source heat pump for residential heating and cooling: A case study of Nanjing, China

This study implemented the performance assessment and techno-economic optimization of residential ground source heat pump (GSHP). First, a detailed numerical model integrating the ground heat exchanger and heat pump and economic model considering economic indicators were developed to analyze the thermal and economic efficiency of residential GSHP. Then, Taguchi method was proposed to investigate the impacts of five parameters on the thermal and economic performance of GSHP and obtain the optimal parameters set. After that, the sensitivity of optimal parameter to the drilling costs, pipe prices, and interest rate were performed. Lastly, the analysis of variance approach was implemented to find out the relative significance of parameters. Results revealing that the superiority of individual GSHP can be maintained in the vast majority of time and the capital investments are relatively high within the range of 13034.4 to 18199.2 CNY. The optimal parameters combination was of great discrepancies when taking the economic indicators into account. The most economical choice of pipe size remains unchanged, despite the optimization objectives and varying pipe prices. The relative importance of fluid velocity, borehole depth, and pipe material towards the variation of economic efficiency largely depends on the drilling costs, pipe prices, and the interest rate.

In-field performance evaluation and economic analysis of residential ground source heat pumps in heating operation

The objective of this study is to investigate the field performance, economic benefits, and environmental impact of ground source heat pumps (GSHPs) for residential space heating compared with conventional natural gas furnaces in a severely cold climate. A total of 32 residential houses with 16 vertical and 16 horizontal loop GSHPs in Iowa, U.S. were included in this study. The required heating energy in each house was estimated by using the heating degree-day (HDD) method and the building characteristics obtained during the on-site energy audits. The monthly GSHP electricity use in each house was collected over two consecutive heating seasons. Based on the estimated heating energy and the monthly GSHP electricity consumption, the coefficient of performance (COP) was derived for each unit on a monthly basis over the dominant heating period. Results showed that the median values in the calculated COP were 2.8 for both horizontal and vertical loop systems. The calculated COPs were found to be 30%–124% of the nominal values for horizontal systems and 46%–110% for vertical systems, with an average being 80% of the nominal value for both horizontal and vertical systems. In addition, 28 out of 32 GSHPs showed lower calculated COPs compared with the nominal values. The economic analysis showed 44–86% savings in energy expenses as a result of using GSHPs in place of conventional natural gas furnaces, with median savings being 70–77% depending on the electricity rates. The environmental analysis showed 23%–61% CO2 emission reduction with a median of 45% compared with natural gas furnaces. These results quantified the economic and environmental benefits of using GSHPs in Iowa, U.S., which provided essential information for policy making and incentive program development. Also, the developed analytical approach to determining the field performance of GSHPs is suitable for large-scale, long-term GSHP performance evaluation given its minimum requirement on field measurements and readily available utility data.

Analytical Comparison of Structure with Reinforced Concrete Wall Against Lateral Load

Buildings are generally designed to withstand against gravity load for expected life and resist extent of lateral loads by satisfying the codal provision. Main objective of structural elements is to transfer the load safely to the ground, which depends on structural system adopted. Generally, structural system can be adopted depending on the demand of client/building needs/use of structure, environmental condition, performance optimization, economic condition etc. For high rise building moment resisting frame system, structural wall systems, dual system, flat slab-structural wall systems can be employed. A residential ground with ten upper floors high rise building situated in zone-III has been taken under reference, where MRF with RC structural wall system is used. Structural parameters are compared in the study for various location and orientation of RC wall. Linear static and dynamic analysis is performed on the structure based on the IS 1893 Part-I on ETABS software.

An empirical analysis on awareness and intention adoption of residential ground source heat pump systems in Greece

Residential heating, cooling and Domestic Hot Water (DHW) production are responsible for a significant part of the residential energy consumption in Greece, which is currently based on the consumption of fossil fuels. A solution for the reduction of fossil fuel use -and all the negative effects that their use implies- is the application of renewable energy technologies, among which Ground Source Heat Pump (GSHP) systems are included. The present study examined awareness and adoption intention issues concerning this technology in Greece, through the conduction of a questionnaire survey. Specifically, it investigated public's knowledge on issues involving this technology, intention of installing it in households, main information sources and installation barriers. Socioeconomic and residence characteristics, as well as consumers’ preferences and attitudes affecting the knowledge and adoption issues were examined. Factors affecting the subjects under investigation are gender, age, education level, environmentally friendly behavior and awareness, as well as having an occupation, studies or interests related to environment, technology or engineering. Additionally, the intention of installing a GSHP system is affected by specific household characteristics, infrastructure and consumers’ preferences on characteristics of heating systems. In order to promote GSHPs, suitable financial incentives, regulatory improvements and awareness activities are required.

Designing Roadside Noise Barrier

Noise is the common problem in the residential area, whether it came from events, vehicles, construction sites, or urban area. The most affected residential area are usually the ones which adjacent to the highway or a road. When someone is overexposed from the noise, this could lead into many health problems. This is why a noise barrier is essential to be built along the road. problems regarding the noise barrier is that although the barrier can attenuates the noise from the traffic, there are other sound source, or in this case, noise source other than the traffic such as the airplane. This problem mostly happened on the residential ground around an airport. One of the solutions for these problems is by using vegetation as additional noise barriers. By doubling the barrier (noise barrier - vegetation) the attenuations will probably much higher, in accounts that the vegetation is much higher than the barrier so that if there are multiple floor buildings, the floors above will also provide with noise insulations. Although, it would be more appropriate to use acoustic treatments to the buildings. The other solution is that by using the concept of constructing a louver or cap atop the wall that is directed back toward the noise source. This concept follows the theory that such a design should inhibit shadow zone diffraction filling in sound behind the noise barrier.
 Keywords: noise, sound, barrier, attenuation

Energy use and carbon reduction potentials from residential ground source heat pumps considering spatial and economic barriers

Ground source heat pump (GSHP) systems are significantly more energy efficient than conventional heating and cooling systems, but they have suffered from low market penetration. This study analyzes the implications of and barriers to nation-wide GSHP retrofits in U.S. single-family houses based on national databases of housing units and home energy use. Our model estimates maximum annual savings of 1.26 quads (1.33EJ) of energy, $7.1 billion in energy costs, and abatement of 64.8 million tons of CO2eq. Economics is the major barrier as typical GSHPs cost $164 less to operate annually but cost $8990 more to install than the conventional alternative HVAC systems. Spatial and economic constraints exclude 7.7% and 89% of homes respectively, leaving only 10% of homes suitable for retrofit. Applying these two constraints, savings reduce to 0.15 quads (0.16EJ), $3.0 billion in energy costs, and abatement of 12.1 million tons of CO2eq. A 30% federal tax credit helps increase the percentage of GSHP-suitable homes from 10% to 30% while reducing the average payback period from 9.1 to 4.8 years among those homes. More effective policies to lower high cost premiums would be needed to promote large-scale GSHP implementations.

Performance of a residential ground source heat pump system in sedimentary rock formation

The use of ground-source heat pump system has been widely adopted over the past decades due to its potentials to provide renewable and low carbon footprint energy source for building’s heating and air-conditioning needs. This paper reports the design and post construction monitoring of a vertical ground-coupled heat pump system installed adjacent to a three-floor residential house located in Cleveland, OH, USA. The system operates under the special geological condition with shallow depth outcrop of sedimentary shale rock formation typical of Northeastern Ohio, USA. A comprehensive monitoring program was installed to collect data on the operation and performance of the ground-coupled heat pump system. The data recording was initialized in Oct. 2012 and has been in place ever since. Overall, the monitoring data shows that the ground heat pump achieved very good performance. The coefficient of performance (COP) of ground coupled heat pump system ranges from 3 to 4. The heat pump satisfies most of the house heating requirements, including severe cold winter, during the monitoring period. This case study demonstrates the feasibility of ground-coupled heat pump system in providing Heating Ventilation and Air Conditioning (HVAC) source for residential building for either heating dominant or cooling dominant conditions under sedimentary rock geological conditions. The possible solutions to decrease the initial investment are proposed in the study.

Seismic Damage Investigation of Residential Fill Ground in the Eastern Part of Kyoto Basin

Several earthquakes record that the residential fills always suffer severe damages. In order to know the seismic damage mechanism and evaluate the damage extent of residential fill ground, research is carried out on two fill grounds in the eastern part of Kyoto basin. The research includes field survey about terrain condition, geological condition, development history, disaster condition during 1995 Kobe earthquake and surface wave explorations. Some remarkable conclusions are summarized as follows: In Jyodo-ji area, it is a residential fill on soft alluvium ground. The geological condition is back swamp. The thickness of surface fill soil is about 1~4 meters. In Kiyomizu-dera area, it is a valley filled ground. The geological condition is hilly platform.

Foundation heat exchangers for residential ground source heat pump systems—Numerical modeling and experimental validation

A new type of ground heat exchanger that utilizes the excavation often made for basements or foundations has been proposed as an alternative to conventional ground heat exchangers. This article describes a numerical model that can be used to size these foundation heat exchanger (FHX) systems. The numerical model is a two-dimensional finite-volume model that considers a wide variety of factors, such as soil freezing and evapotranspiration. The FHX numerical model is validated with one year of experimental data collected at an experimental house located near Oak Ridge, Tennessee. The model shows good agreement with the experimental data—heat pump entering fluid temperatures typically within 1°C (1.8°F)—with minor discrepancies due to approximations, such as constant moisture content throughout the year, uniform evapotranspiration over the seasons, and lack of ground shading in the model.

Sub-hourly simulation of residential ground coupled heat pump systems

Residential Ground Coupled Heat Pump systems are usually characterised by an ON/OFF behaviour of the heat pump with typical cycling frequencies of 1—4 cycles per hour. The ground loop fluid pump has the same ON/OFF behaviour and the borehole heat exchanger operates either in full flow or no flow conditions. Typical hourly simulations of GCHP systems use steady-state models for the heat pump and the borehole fluid (transient models being used for buildings and heat transfer in the ground). This paper reviews the models used in typical hourly simulations as well as transient models that are available and compares the results obtained using the two classes of models within the TRNSYS simulation environment. Both the long-term energy performance and the optimum system design are compared. It is shown that using steady-state models leads to an overestimation of the energy use that ranges from a few percents with oversized borehole heat exchangers to 75% for undersized exchangers. A simple Life Cycle Cost analysis shows that using steady-state models can lead to selecting a very different design than the one that would have been selected using dynamic models.

表面波探査と動的弾塑性ＦＥＭに基づく緩傾斜宅地の簡易な耐震性能評価

Two typical suffering cases of slightly-inclined residential ground at the time of Mid Niigata Prefecture Earthquake 2004 are examined. Around the houses on the thickly filled ground, large residual settlement was observed clearly. Probably, the liquefaction of saturated sand in the ground may be related to the damage. In this study, the mechanism of damage is examined based on the 2-D dynamic elasto-plastic finite element method. In the analysis, the material parameters have been determined based on the distribution of shear wave velocity in the ground, which was estimated by the surface-wave investigation. It is shown that the dynamic elasto-plastic finite element analysis with the surface-wave investigation is very effective for the evaluation of the seismic stability of the ground.

ELF Magnetic Fields, Transients and TWA Metrics

Residential measurements of ambient power frequency magnetic fields may serve as surrogates for personal exposures. There are few data available, however, to determine how far back in time this surrogacy holds. A limited amount of research on residential transients suggests that, all other factors being equivalent, larger transients may propagate within VHCC neighbourhoods than within LCC neighbourhoods. However, the presence of a conductive residential ground pathway also appears to be a potentially important factor associated with residential transient activity. The use of the TWA metric was prompted by the need for an exposure score simple enough to summarise an individual's exposure over a prior interval, yet specific to the agent of concern, namely the power frequency magnetic field. To the extent that the TWA exposure is associated with health outcomes in the absence of bias, including confounding, the TWA metric is important.