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Using conjoint choice experiments, we surveyed 473 Swiss homeowners about their preferences for energy efficiency home renovations. We find that homeowners are responsive to the upfront costs of the renovation projects, governmentoffered rebates, savings in energy expenses, time horizon over which such savings would be realized, and thermal comfort improvement. The implicit discount rate is low, ranging from 1.5 to 3%, depending on model specification. This is consistent with Hassett and Metcalf (1993) and Metcalf and Rosenthal (1995), and with the fact that our scenarios contain no uncertainty. Respondents who feel completely uncertain about future energy prices are more likely to select the status quo (no renovations) in any given choice task and weight the costs of the investments more heavily than the financial gains (subsidies and savings on the energy bills). Renovations are more likely when respondents believe that climate change considerations are important determinants of home renovations.

This paper deals with the thermal performances of shape-stabilized phase change materials (SSPCM) for energy saving in various fields. This study enhanced thermal properties of SSPCM using exfoliated graphite nanoplatelets (xGnP). SSPCM, which contains the xGnP, was prepared by mixing and melting techniques for high dispersibility, thermal conductivity, and latent heat storage. In the experiment, we used hexadecane, octadecane, and paraffin as phase change materials (PCMs), and they have 254.7, 247.6, and 144.6 J g−1 of latent heat capacity, and melting points of 20.84, 30.4, and 57.09 °C, respectively. The characteristics of SSPCMs were determined using SEM, DSC, FTIR, TG, TCi, and Energy simulation. SEM morphology showed homogenous dispersion of PCM and xGnP in the porous diatomite. DSC analysis results showed the latent heat capacity of SSPCM and SSPCM/xGnP composites, and TG analysis results showed the thermal reliability of the samples. Also, we checked the thermal conductivity of the SSPCM that contains xGnP, by TCi analysis.

Air curtains are used to reduce the heat and mass exchange across open doorways. Their sealing ability is assessed in terms of the effectiveness $\\def \\xmlpi #1{}\\def \\mathsfbi #1{\\boldsymbol {\\mathsf {#1}}}\\let \\le =\\leqslant \\let \\leq =\\leqslant \\let \\ge =\\geqslant \\let \\geq =\\geqslant \\def \\Pr {\\mathit {Pr}}\\def \\Fr {\\mathit {Fr}}\\def \\Rey {\\mathit {Re}}E$ , the fraction of the exchange flow prevented by the air curtain compared to an unobstructed open door. Previous work has studied air-curtain effectiveness when the doorway is the only means of ventilating a space. In this paper, we examine the effects of additional displacement ventilation on the dynamics of the air curtain and the resulting changes in its effectiveness. The main controlling parameter is the deflection modulus $D_{m}$ , which is the ratio between the momentum flux of the air curtain and the transverse forces due to the displacement ventilation. For a relatively warm interior, we find that, for small values of $D_{m}$ , the air curtain is drawn inside the space by the ventilation flow. For large values of $D_{m}$ , the flow through the doorway is controlled by the air curtain. A smooth transition occurs between these two regimes, and we estimate the $D_{m}$ value for the onset of this transition. Our model provides a quantitative prediction of $E(D_{m})$ in the ventilation-driven regime, and gives a qualitative description of the other two regimes. Laboratory experiments were conducted to test the proposed model. The experimental data were compared to theoretical predictions, and good agreement was found.

The heating and cooling of buildings represents a big chunk of global energy needs and a significant cause of carbon dioxide emissions. There is thus growing use worldwide of so-called ‘energy geo-structures’ – particularly piles – which take advantage of the relatively constant temperature of the underlying ground to reduce building energy requirements. Fluid circulating in pipes in such structures can extract heat from the ground to help heat a building in winter and can expel excess heat from air conditioning in summer. However, this introduces potentially serious additional stresses and strains which need to be considered during design – though they seldom are. This paper describes recent research into the thermo-mechanical behaviour of energy piles to help ensure they are properly designed.

There is a wide consensus that buildings, as major energy consumers and sources of greenhouse gas emissions must play an important role in mitigating climate change. This has led to increasing concern and greater demand to improve energy efficiency in buildings. Although, there has been increased efforts to reduce energy consumption from existing building stock; the heritage sector still needs to accelerate its efforts to improve energy efficiency and reduction in greenhouse gas emissions. Presently, much concentration has been on improving the energy efficiency of heritage buildings in the domestic sector while, the non-domestic sector has only received little attention. In particular, studies focusing on reuse and adaptation of heritage buildings for public use to achieve more efficient use of energy are urgently required. The main focus of this paper is the need for research into sustainable reuse of public heritage buildings with reference to maximising energy efficiency in the process of considering their conversion to other uses. The paper presents part of a broader on-going research with the aim to investigate problems associated with maximising energy efficiency in reuse and conversion of public heritage buildings. It identifies the ability of heritage buildings to play a role in global reduction of energy use and CO2 emission whilst maintaining its unique characteristics. Issues and challenges associated to improving energy efficiency in heritage building conversion projects were discussed. Holistic approach through identification of various options and innovative techniques for their sustainable reuse were suggested. The paper concluded that in spite of the exemption of listed buildings from energy performance requirements, these buildings can still accommodate some energy efficiency improvements. However, further studies to identify the most suitable options for long term sustainability is required if the goal to reduce greenhouse gas emissions by 80% by 2050 is to be achieved.

Energy use for domestic purposes can be considered as the prime consumer of Pakistan's energy resources. Residential buildings are one of the consumers of energy for space cooling. In this paper we studied the energy consumption for space cooling of a residential building for located in Islamabad. The relevant data of construction, operation schedules, occupancy and lighting of the selected residential building was collected and analyzed through simulation using eQuest energy simulation tool. The model was considered as the baseline model for further analysis. Energy efficiency measures were applied to windows area, windows glazing type, Area lighting, heating ventilating and air conditioning (HVAC) system thermostat set point and Energy Efficiency ratio of the HVAC system. Results showed 38.5 % decrease in the energy consumption as compared to the baseline model.

Factorial design approach was undertaken to determine the effect of initial moist-curing duration (0 and 6 days) on properties of high-performance concrete (HPC) made with different water-to-cementitious materials ratios (w/cm) of 0.30 and 0.40 and sand substitution rates with lightweight sand (LWS) of 0 and 30 %, by volume. Mechanical properties of HPC are shown to be mainly affected by w/cm and total shrinkage of concrete by the LWS replacement rate and initial moist-curing period. It should be noted that concrete made with 30 % LWS replacement that did not receive any moist-curing exhibited lower shrinkage than moist-cured concrete prepared without any LWS, regardless of the w/cm. Combined use of 30 % LWS and 7 days of moist curing can lead to greater increase in compressive strength and larger decrease in total shrinkage compared to the use of 30 % LWS without moist curing or 7 days of moist curing without LWS. The use of LWS, however, is more practical and efficient to reduce shrinkage of HPC for deep concrete elements.

Air conditioning energy consumption in summer represents a challenge in many areas with hot and humid climates. Passive cooling with thermal storage in phase change materials (PCMs) is a very effective way to improve thermal stability of the rooms with light-weight envelope. The main objective of this research is to demonstrate experimentally that it is possible to improve the thermal comfort and reduce the energy consumption of a building without substantial increase in the weight of the construction materials with the inclusion of PCM. This work aims at presenting an overview of the key researches in the field of use of PCMs in buildings and presenting a green approach for their uses in building envelopes with specific implementation on the case of hot humid regions. Thermal behaviour of wall integrated with two different types of PCMS Polyethylene glycol (PEG) E600 and Capric Acid (C10 H20 O 2) was compared by measurements and calculations. Three test cells were built for comparative investigation of the efficiency of passive cooling with the use of the PCMs. This paper deals with the results of experiments carried out in the test cells and possibilities of activation of PCMs for effective passive cooling.

The objective of this study was to perform a daylighting analysis on the light shelf system installed to save energy in office buildings in Tamil Nadu. For this, a building was chosen for energy analysis simulation using Ecotect software. Light shelves with four different patterns of diffuse reflections in increasing levels were chosen at the preliminary stage. The illuminance was highest in the mirror finish followed by high reflective, medium reflective and light reflective partitions. The light shelf with the mirror finish was chosen for the economic analysis since it is more efficient than other diffuse reflection panels. Results of the economic analysis showed that lighting energy consumption was reduced by an average of 30% using the mirror finished light shelf with energy efficient lamps, compared with the base case model where lighting control was not applied. A simple payback period, calculated for the model with the light shelf system installed was 6 years and 4 months.

The design of historic building conservative restoration based on Eco- Architecture principles is the theme considered here. The recovery of buildings subjected to preservation in order to use them for modern functions is a widespread problem in many old European cities. This exigency arises from the observation that often only a real utilization justifies the costs of the refurbishment and of the following maintenance work. But the existing restrictions usually prevent working on the building envelope to reduce the energy demand. However, the sustainability of the restoration cannot ignore the strict requirements about energy consumption and management cost reduction. It is therefore necessary to focus the intervention on the energy efficiency of the plants taking the opportunity to exploit the renewable energies even more than in new buildings. The case of the former convent of the Crucifers in Venice is presented here. The lagoon environment suggests the use of the surface waters coupled with a heat pump as renewable energy source. The modeling of the building-plant system and the consequent simulation of the annual energy performances permit the comparison between the adopted solution and the other alternatives. The study points out the possibility of achieving significant energy savings.