The Impact of Modern Artificial Lighting on the Optimum Window-to-Wall Ratio of Residential Buildings in Jordan

Energy savings gained through natural lighting could be offset by the loss of energy through windows; therefore, the target of this study is to examine the effects of enhancing the efficiency of lighting systems on the optimum window-to-wall ratio (WWR) of Jordanian residential structures. This research proposes the hypothesis that the WWR of residential structures that contain artificial lighting systems with increased efficiency will be lower than buildings in which solar lighting is provided. The energy simulation tool, DesignBuilder, was used to simulate an intricate model showing a standard Jordanian residential building with a size of 130 m2. The study offers useful guidance regarding the optimum WWR for key decisionmakers when designing energy-efficient residential structures in the context of Jordan. By considering the balance between gains and losses in solar heat and light gain to exploit energy from solar sources with no reverse effects, while making comparisons between different WWR situations, the findings indicate that the typical WWR for residential structures in Jordan that have efficient Light Emitting Diode (LED) systems of lighting installed could be between 25% and 30%, which is lower than the highest WWR stipulated by the ASHRAE standards.

Impact of window walls on thermal comfort and energy efficiency in condominium buildings: an experimental study in Toronto

Radiant field asymmetry is described as differences in radiant temperature an occupant perceives on different parts of the body. Most complaints about thermal comfort in condominiums are as a result of local discomfort rather than overall discomfort. A field study was performed in summer, using thermocouples to determine possible thermal discomfort caused by the interior surface temperature of a window wall oriented with marginal solar radiation and its effects on energy efficiency. ASHRAE standard 55 was used to evaluate thermal comfort while temperature gradients between the window wall temperature and a “neutral” window wall temperature was used to evaluate energy efficiency of the window wall. Results showed that on a hot clear day there was a rise in interior surface temperature of the window wall by 8.4ºC, due to direct solar radiation. Thermal comfort was within ASHRAE standards and energy efficiency would have been improved with a better window to wall ratio or high performance

Impact of window walls on thermal comfort and energy efficiency in condominium buildings: an experimental study in Toronto

Radiant field asymmetry is described as differences in radiant temperature an occupant perceives on different parts of the body. Most complaints about thermal comfort in condominiums are as a result of local discomfort rather than overall discomfort. A field study was performed in summer, using thermocouples to determine possible thermal discomfort caused by the interior surface temperature of a window wall oriented with marginal solar radiation and its effects on energy efficiency. ASHRAE standard 55 was used to evaluate thermal comfort while temperature gradients between the window wall temperature and a “neutral” window wall temperature was used to evaluate energy efficiency of the window wall. Results showed that on a hot clear day there was a rise in interior surface temperature of the window wall by 8.4ºC, due to direct solar radiation. Thermal comfort was within ASHRAE standards and energy efficiency would have been improved with a better window to wall ratio or high performance

Must attic ventilation be preserved in energy retrofits?

Purpose The addition of thermal insulation into attics along with air-tightening of the ceiling plane is a common first step in making homes more energy efficient. Attic ventilation was introduced decades ago on the assumption that air leakage across the ceiling was inevitable and not correctible – this was before the era of spray-applied foams. Often attic ventilation is provided at roof eaves, and ensuring good insulation in their location is critical to avoid cold corners in the rooms below. So may vents be blocked in the course of energy retrofits? The paper aims to discuss this issue. Design/methodology/approach This study consists of a simple spreadsheet model of attic performance. The model is built using material from ASHRAE Handbook Fundamentals and ASHRAE Standards. It includes: Glaser calculations for temperature, vapor pressure and vapor pressure excess; radiation exchange – solar and sky; buoyancy flow assumption for leakage from indoors; wind flow assumption for leakage from outdoors; and change in attic air RH as assumed indicator of change in sheathing moisture performance. Findings The model results show that lowered moisture contributions across air-tightened ceilings may compensate effectively for added insulation (which lowers the attic air temperature) and reduced moisture dilution from attic ventilation. Originality/value These results provide support for the policy of allowing attic ventilation reductions that are proportionate to ceiling air leakage reductions as part of weatherization efforts. Given the limitations of the model, continued field observations remain critical.

Framework for the Detection, Diagnosis, and Evaluation of Thermal Bridges Using Infrared Thermography and Unmanned Aerial Vehicles

The glass curtain wall system is an architectural, functional innovation where failures of insulation systems create areas of reduced resistance to heat transfer—thermal bridges—during a building’s operational lifetime. These failures enable energy flows that trigger unanticipated temperature changes and increased energy consumption, ultimately damaging the façade structure and directly impacting occupants. Our study aims to design and test an innovative method for rapidly identifying thermal bridges in façade systems, with minimum or no occupant disturbance. The research focus is in the classification of damage as either a local failure or as being related to a poor systematic construction/assembly. A nontraditional approach is adopted to survey an entire fully operational building using infrared thermography and an unmanned aerial vehicle (UAV) using a noncontact infrared camera mounted on and operated from the UAV. The system records the emissivity of the façade materials and calculates the thermal radiation to estimate localized temperatures. The system records thermal radiation readings which are analyzed using graphs to be compared with the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standards, under ideal conditions using the THERM software. The results enable discussion relating to the most common failure areas for existing structures, facilitating the identification of focus areas for the improvement of construction methods through improved processes.

Hydrocarbons as Refrigerants―A Review

Refrigerants used in air conditioning and refrigeration (AC&R) indusries have come full circle since the beginning of the industrialrevolution. With concern on issues relating to the environment such as the global warming and climate change issues, we should finda better alternative than to continue using these refrigerants that cause global warming and ozone depletion. AC&R industryplayers have blended in by introducing some new equipment and components that are specificallydesigned for hydrocarbon (HC) use. Mostnew refrigerators sold in Malaysia are already equipped with isobutane [a hydrocarbon designated as R-600a by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards]as refrigerants. Malaysia has ratifiedthe Montreal Protocol and targetted a 10% reduction in hydrochlorofluorocarbon(HCFC) consumption, beginning 2016 with the banning of 2.5 horsepower (hp) and below in air-conditioning (AC) equipment to be used. Instead,hydrofluorocarbon(HFC) R-410a was introduced as a replacement for HCFC- 22, whereas in other countries this HFC has been phased down. This article was initiated because of the difficultin findinga replacement for HCFC. Also, the possibilities of using HC as an alternative to replace HCFC insteadof using HFC as a transitional refrigerant in place of HCFC is reviewed in this article. The performance of HC is very similar to HCFC and flmmability issues could be easily overcome with the use of an effectivedesign. Their use could be facilitated with the adaptation of specific standards and properly enacted legislatio

On the Choice of Suitable Parameters for the Assessment of Industrial Fans Performance and Efficiency

More than half a century has been spent by technicians involved in fans testing to suggest and fix best practice procedures including also the definitions of several performance and efficiency parameters (e.g., ISO, AMCA, ASHRAE Standards...). However, the huge amount of energy used by ventilation systems and the recent introduction of the stringent European Community regulations on Energy Related Products, suggests to spend additional time on the ancient question about which and how many should be the parameters best suited to classify the performance of fans and their capability to properly use the energy input. This also because there are some attempts to fix the fan total-to-static pressure rise and the related total-to-static efficiency as the only two parameters required to assess the fan quality. Starting from basic thermodynamic principles, this paper tries to shed light on the parameters that are best suited to assess fan performance and efficiency. The general layout of a ventilation system is discussed to clearly show which and how many are the parameters required for the optimal matching between fan and system. Finally, some comments on practical advantages and drawbacks in the operation of the fan at the total-to-static best efficiency point are presented as well.