scholarly journals In-Service Thermal and Luminous Performance Monitoring of a Refurbished Building with Solar Control Films on the Glazing System

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1388
Author(s):  
Henriqueta Teixeira ◽  
Maria da Glória Gomes ◽  
António Moret Rodrigues ◽  
Júlia Pereira
Keyword(s):  
Thermal Comfort ◽  
Thermal Performance ◽  
Performance Monitoring ◽  
Energy Use ◽  
Positive Impact ◽  
Radiation Absorption ◽  
Cooling Period ◽  
Heating And Cooling ◽  
Solar Control ◽  
Office Rooms

The global increase in energy needs and environmental awareness for a more efficient energy use have boosted building rehabilitation to decrease energy consumption. The installation of solar control films (SCFs) in buildings with large glazing façades makes it possible to reduce excessive solar gains through the glazing. The main purpose of the work is to assess, with field experimental data, the thermal and luminous performances of double-glazing units with SCFs installed in office rooms, in Lisbon. An experimental campaign was carried out simultaneously in three adjacent offices: one with a highly reflective SCF (external installation), one with a reflective SCF (internal installation) and one without an SCF. The exterior SCF showed the best thermal performance with reductions in the peak indoor air temperature of up to 6.9 and 2.3 °C during the representative days of the heating and cooling periods, respectively, increasing thermal comfort mainly during the cooling period. The interior SCF had a poorer thermal performance since it contributed to solar radiation absorption that is then emitted as heat into the indoor environment, increasing the greenhouse effect of the office. The presence of SCFs reduced the indoor illuminance levels, having a positive impact on thermal comfort and glare reduction in the cooling period.

scholarly journals Thermal mass and the effects on heating and cooling demands – an experimental study of an exposed concrete floor

2020 ◽  
Vol 172 ◽  
pp. 03004
Author(s):  
Alessandro Nocente ◽  
Steinar Grynning
Keyword(s):  
Energy Demand ◽  
Energy Use ◽  
Positive Impact ◽  
Thermal Mass ◽  
Wooden Floor ◽  
Heating Systems ◽  
Heating And Cooling ◽  
Experimental Campaign ◽  
Office Rooms ◽  
Positive Effect

The increase of thermal mass in buildings is discussed as a useful measure for reducing the energy demand for heating and cooling while contributing to improve the internal comfort. Several studies confirmed its positive effect, but few conducted a solid comparative measurement campaign and rarely in comparative conditions. The present work reports the results of an extensive comparative campaign in a test cell facility, where the internal conditions are measured in two identical rooms. One of the rooms was equipped with a large concrete mass while the other was constructed with a thin wooden floor. Measurements were conducted for circa a month, divided in four phases. The internal temperature of the two rooms was kept within typical boundaries of actual office rooms by a water-based cooling and heating systems. The energy demand of both heating and cooling was measured. Occupancy was simulated by a mannequin and by the lighting, both active only in office hours. The results demonstrated a positive impact of the thermal mass on the energy use. Since the test rooms are highly insulated, the energy use associated to cooling was dominant. During the experimental campaign, a reduction of up to 44% of the energy demand due to cooling was registered.

scholarly journals Analysis of heating and cooling periods in Budapest using station data

Időjárás ◽  
2021 ◽  
Vol 125 (3) ◽  
pp. 431-448
Author(s):  
Csenge Dian ◽  
Attila Talamon ◽  
Rita Pongrácz ◽  
Judit Bartholy
Keyword(s):  
Energy Use ◽  
Transitional Period ◽  
Design Parameters ◽  
Data Series ◽  
Total Energy Consumption ◽  
Regional Warming ◽  
Cooling Systems ◽  
Cooling Period ◽  
Heating And Cooling ◽  
The One

The built environment has a very complex role in cities. On the one hand, various urban climatological phenomena are caused and influenced by buildings (e.g., urban heat island effect, local wind conditions, air pollution). On the other hand, buildings are important contributors to energy use via heating and cooling, e.g. they account for about 40% of total energy consumption on average in Europe. Daily average outdoor temperature is taken into account to design the heating and cooling systems of residential, commercial, or office buildings. That is why we analyzed the available temperature time series of the capital of Hungary, Budapest for the period between 1901 and 2019. The aims of this study are (i) to investigate the changes in temperature data series that influence building energy design parameters, (ii) to analyze the heating and cooling periods in the last 119 years based on different definitions, and (iii) to define a third (transitional) period between the heating and cooling periods. Based on the results, it can be concluded that the variability of warm days is smaller than that of cold days, consequently, the optimal design of heating systems is a greater challenge compared to cooling systems. Furthermore, the length of the temperature-based heating period decreased substantially, while the length of the cooling period increased as a consequence of overall regional warming.

scholarly journals Thermal Performance of Resource-Efficient Geopolymeric Mortars Containing Phase Change Materials

2018 ◽  
Vol 12 (1) ◽  
pp. 217-233
Author(s):  
M. Kheradmand ◽  
F. Pacheco-Torgal ◽  
M. Azenha
Keyword(s):  
Phase Change ◽  
Thermal Performance ◽  
Phase Change Materials ◽  
Positive Impact ◽  
Performance Testing ◽  
Cost Effective ◽  
Small Scale ◽  
Heating And Cooling ◽  
Reduce Emissions ◽  
Cooling Loads

Background:Energy efficiency is not only the most cost effective way to reduce emissions but also a way to improve competitiveness and create employment. Geopolymeric mortars containing phase change materials-PCMs have a twofold positive impact concerning eco-efficiency. On one hand, the mortars are based on industrial waste contributing for resource efficiency. And on the other hand, PCM based mortars have the capacity to enhance the thermal performance of the buildings.Objective:This paper reports experimental results on the thermal performance of geopolymeric mortars containing different percentages of phase-change materials-PCMs.Method:Five groups of alkali-activated based mortars with different PCM percentages were produced and placed on a panel within a small scale prototype for thermal performance testing.Results:The results show that the thermal conductivity of the mortars decreased with the increase in the percentage of the PCM.Conclusion:Thermal performance of the PCM based mortars allowed for a stronger attenuation of the temperature amplitudes. Both for heating and cooling loads.

Design and Performance of the Van Geet Off-Grid Home

2004 ◽  
Vol 126 (2) ◽  
pp. 738-743 ◽  
Author(s):  
C. Dennis Barley ◽  
Paul Torcellini ◽  
Otto Van Geet
Keyword(s):  
Computer Simulation ◽  
Energy Efficient ◽  
Performance Monitoring ◽  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Hot Water ◽  
Domestic Water ◽  
Heating And Cooling ◽  
And Performance

The Van Geet home near Denver, Colorado, demonstrates the successful integration of energy conservation measures and renewable energy supply in a beautiful, comfortable, energy-efficient, 295-m23,176-ft2 off-grid home in a cold, sunny climate. Features include a tight envelope, energy-efficient appliances, passive solar heating (direct gain and Trombe wall), natural cooling, solar hot water, and photovoltaics. In addition to describing this house and its performance, this paper describes the recommended design process of (1) setting a goal for energy efficiency at the outset, (2) applying rules of thumb, and (3) using computer simulation to fine-tune the design. Performance monitoring and computer simulation are combined for the best possible analysis of energy performance. In this case, energy savings are estimated as 89% heating and cooling (compared to 95 MEC), 83% electrical, and nearly 100% domestic water heating. The heating and cooling energy use is 8.96kJ/°Cs˙days˙m20.44Btu/°Fs˙days˙ft2.

scholarly journals Evaluating the impact of different pipe arrangements on the thermal performance of thermo-active piles

2020 ◽  
Vol 205 ◽  
pp. 05006
Author(s):  
Ryan Y. W. Liu ◽  
Eleonora Sailer ◽  
David M. G. Taborda ◽  
David M. Potts
Keyword(s):  
Thermal Performance ◽  
Energy Use ◽  
Near Field ◽  
Heat Fluxes ◽  
Far Field ◽  
Low Carbon ◽  
Finite Element Analyses ◽  
Heating And Cooling ◽  
The Impact ◽  
Evolution With Time

Thermo-active piles are widely utilised for low carbon heating and cooling, and their uses are further encouraged in cities where there are obligations for developments larger than a certain threshold to generate a portion of their estimated energy use on site in a renewable manner. It is therefore important to model accurately the thermal performance of the designed thermo-active piles to ensure that such obligations are complied with. In this paper, the thermal performance of a thermo-active pile is quantified by the evolution with time of the power that can be harnessed from the pile, obtained from 3D thermo-hydro-mechanically coupled finite element analyses which include the simulation of a hot fluid flowing through heat exchanger pipes. Different pipe arrangements are considered in this study, in order to demonstrate the potential gains in efficiency arising from the installation of multiple U-loops within the pile. Furthermore, detailed analysis of the heat fluxes resulting from pipe-pile-soil interaction is carried out, illustrating the contribution of the different components of the system (concrete, near-field and far-field) to the overall storage of thermal energy.

scholarly journals Behavioural Adaptation for the Thermal Comfort and Energy Saving in Japanese Offices

2019 ◽  
Vol 15 (2) ◽  
pp. 14-25
Author(s):  
Hom B. Rijal ◽  
Michael A. Humphreys ◽  
J. Fergus Nicol
Keyword(s):  
Thermal Comfort ◽  
Energy Use ◽  
Thermal Environment ◽  
Office Buildings ◽  
Behavioural Adaptation ◽  
Indoor Thermal Environment ◽  
Heating And Cooling ◽  
Adaptive Thermal Comfort ◽  
Window Opening ◽  
Behavioural Adaptations

Office workers use a variety of adaptive opportunities to regulate their indoor thermal environment. The behavioural adaptations such as window opening, clothing adjustments, and use of heating/cooling are important factors for adaptive thermal comfort. It is well-known that they are the most important contributors in the adaptive thermal comfort model. Thus, if we understand the behavioural adaptation properly, we can explain the mechanism of the adaptive model. The indoor thermal environment is often adjusted using the air conditioning in Japanese office buildings to improve thermal comfort and productivity. Thus, it is necessary to conduct research on the behavioural adaptation in the offices because the occupant behavior is different from behaviour in dwellings. In order to record the seasonal differences in behavioural adaptation and to develop an adaptive algorithm for Japanese offices, we measured temperatures in 11 office buildings and conducted the thermal comfort and occupant behaviour survey for over a year. We collected 4,660 samples from about 1,350 people. The proportion of ‘open window’ in the free running mode (neither heating nor cooling being used) is significantly higher than that of the air conditioned mode. The behavioural adaptation is related to the outdoor air temperature. The behavioural adaptations such as window-opening, heating and cooling use predicted by regression analysis are in good agreement with the measured data. These findings can be applied to building thermal simulation to predict the behavioural adaptation and energy use in office buildings.

scholarly journals Tuning radiative heat flows between interior surfaces and human occupants to improve heating and cooling efficiency

2020 ◽  
Author(s):  
Jin Xu ◽  
Aaswath Raman
Keyword(s):  
Thermal Comfort ◽  
Energy Use ◽  
Energy Savings ◽  
Weather Conditions ◽  
Cold Weather ◽  
Set Point ◽  
Heating And Cooling ◽  
Building Surfaces ◽  
Interior Walls ◽  
High Emissivity

Space heating and cooling in buildings account for nearly 20% of energy use globally. In most buildings this energy is used to maintain the thermal comfort of the building’s human occupants by maintaining the interior air temperature at a particular set point. However, if one could maintain the human occupant’s thermal comfort while decreasing the heating or increasing the cooling set point, dramatic energy savings are possible. Here, we propose and evaluate an untapped degree of freedom in improving building efficiency: dynamically tuning the thermal emissivity of interior building surfaces at long-wave infrared wavelengths to maintain thermal comfort. We show that in cold weather conditions tuning the emissivity of interior walls, floors and ceilings to a low value (0.1) can decrease the set point temperature as much as 7°C, corresponding to an energy saving of nearly 67.7% relative to high emissivity materials (0.9). Conversely, in warm weather, high emissivity interior surfaces result in a 38.5% energy savings relative to low emissivity surfaces, highlighting the need for tunability for maximal year-round efficiency. Our results reveal the remarkable energy savings potential possible by better controlling the ubiquitous flows of heat that surround us in the form of thermal radiation.

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