Internal Gains Research Articles

Numerical test bench to evaluate the influence of heat gains on the estimation of Heat Transfer Coefficient under occupied conditions

The estimation of the HTC heat transfer coefficient in real occupancy conditions has a great operational advantage contrary to the measurement in unoccupied conditions, which requires specific measurement protocols. Nevertheless, it presents additional constraints because the gains due to weather conditions and occupancy are poorly controlled. The objective of this work is therefore to quantify the impact of these different gains. A numerical test bench is set up to study the impact of the solar and internal gains by varying different parameters, such as the typology of the building, the meteorological conditions, the scenarios of occupancy. These numerical tests allow to estimate the HTC of a building by calibrating a numerical model from a virtual dataset generated by a detailed model with known and controlled meteorological conditions and usage conditions. They make it possible to determine the share of solar heat gain and internal heat gain in the energy balance of the building and their impact on the estimation of the HTC according to the studied configurations.

Influence of passive solar gains on the energy consumption of a typical house in Algiers

The purpose of a bioclimatic house is to make every effort to reduce the need for heating and cooling. For this a well studied architecture of the house is essential: - the positioning of windows to capture the maximum solar radiation, - Good thermal insulation of the house to reduce heat loss. This study focuses on the effect of solar and internal heat gain on the energy consumption of a typical well insulated house. The degree day’s method is used to determine the heat losses by transmission and ventilation according to international standards on thermal insulation of building (NBN B62-301), the results are very interesting and promising. By including the solar and internal gains, which vary from 900 to 1400 kWh, the energy consumption decreases significantly. The thermal load for heat reaches 60 kWh, but by including the free thermal gains, 10 kWh of energy can be saved daily.

The impact of a kinetic façade on the lighting performance and energy efficiency of a public building: the case of Dubai frame

ABSTRACT This paper proposes a novel framework for selecting a kinetic system strategy to enhance the performance of the building while preserving its architectural concepts. Dubai Frame, which is one of the most iconic buildings in Dubai, was chosen to act as a case study. A parametric model was developed for adjusting the opening ratios of the panel’s solid parts in the façade geometrics using the Grasshopper plugin in Rhino. Integrated Environmental Solutions (IES) simulation software was used and validated by calibration of the actual monthly electricity bills and real measurement of lux value against the predicted readings. The simulation assessed the total energy savings in terms of electricity and cooling loads and cost savings in terms of the KW per hour of electricity generated. In addition, it examined daylight illuminance levels for nine scenarios of the proposed kinetic system. The research has revealed several important results that include the finding that the optimal kinetic system results in 20% energy savings and 31% reduction in daylight illuminance levels while taking into account the current situation of the building and its aesthetic values. Abbreviations: UAE, United Arab Emirates; IEQ, Indoor Environmental Quality; PCM, Phase change materials; ASHRAE, The American Society of Heating, Refrigerating and Air-Conditioning Engineers; LEED, Leadership in Energy and Environmental Design system; HVAC, Heating, ventilation and air conditioning; RH, Relative Humidity; WWR, Window Wall Ratio; LR, Literature Review; RSMF, Room Surface maintenance factor; LMF, Luminaire maintenance factor; VAT, Value added tax; IHG, Internal Heat Gains

Theoretical Minimum Thermal Load in Buildings

Summary Building cooling and heating accounts for a large portion of total global energy use and requires commensurate amounts of resources, which contribute significantly to global warming. Traditionally, addressing this issue has meant improving the efficiency of equipment supplying the thermal energy, reducing envelope heat transfer, and reducing air infiltration. However, this approach is already reaching practical limits. In this perspective, we explore (1) how to reduce thermal load in buildings theoretically and (2) how to achieve that reduction and dramatically lower the energy required to support building loads practically. First, we discuss our framework developed for calculating the theoretical minimum thermal load (TMTL) in buildings. Our analysis shows that current thermal loads in buildings are more than an order of magnitude higher than the TMTL. We also introduce an approximate formula to calculate energy savings from zonal control of thermal load, which shows that the majority of zonal control benefits can be achieved with fewer than 10 zones. Then, we discuss pros and cons of various approaches and strategies to achieve the TMTL. We conclude our perspective with some longer-term R&D ideas, such as thermally adaptive clothing and thermal storage to help approach the TMTL, while providing the additional benefit of interacting with the renewable grid of the future.

Pengaruh Pengendalian Internal, Sistim Informasi Akuntansi Terhadap Efisiensi Biaya, Efektivitas Pelayanan Medis dan Non Medis Pada PT Rumah Sakit Pelni

The purpose of this study was to determine the effect of the Internal Control and Accounting Information Systems Cost Efficiency And Effectiveness Of Medical And Non-Medical Services (Studies in Hospital Pelni). The independent variable of this study is the Internal Control and Accounting Information Systems. The dependent variable of this study is Cost-Efficiency and Effectiveness of Medical and Non-Medical Services. The research method used is explanatory survey with a cross-sectional methods, while the sampling technique is convenience sampling with instruments of research using questionnaires in 58 respondents in Pelni Hospital. Data were analyzed quantitatively by regression analysis. Results of the study (1) Internal Control Influential Efficiency Gains and Cost Effectiveness of Medical and Non-Medical Services (2) Impact of Accounting Information Systems Gains Efficiency And Cost Effectiveness of Medical and Non-Medical Services (3) Simultaneously Internal Control and Accounting Information Systems Influential Significant Cost Efficiency And Effectiveness of Medical and Non-Medical Services. 
 Keywords: Internal Control, Accounting Information Systems, Efficiency and Cost Effectiveness of Medical and Non-Medical Services

Effect of occupant behavior on peak cooling and dehumidification loads in typical and high-efficiency homes

Residential building codes and voluntary labeling programs are continually increasing the energy efficiency requirements of residential buildings. Improving a building’s thermal enclosure, installing the ductwork in conditioned space, and improving the building’s airtightness results in significant reductions in externally-driven sensible and latent cooling loads. As a building’s efficiency is improved, occupant-related internal gains become a larger portion of the building sensible and latent loads. Additionally, internal gains are highly uncertain compared to other load components. In this study, we use a stochastic approach to simulate occupant-related internal gains and compare the internal gains to other sensible and latent heat sources in four house efficiency levels in 10 U.S. climates using whole-building energy simulation software. We compare the expected range in occupant-related internal gains to other building characteristics such as cooling set point, air infiltration rate, and mechanical ventilation rate. We show that in high-efficiency homes, sensible internal gains vary from less than 10% to greater than 40% of the building sensible load under peak total cooling conditions depending on climate and internal gain profile. Likewise, latent internal gains vary from less than 10% to more than 60% of the building latent load under peak total cooling and peak dehumidification conditions depending on climate and internal gain profile.

Adaptive thermal comfort opportunities for dwellings: Providing thermal comfort only when and where needed in dwellings in the Netherlands

Adaptive thermal comfort opportunities for dwellings: Providing thermal comfort only when and where needed in dwellings in the Netherlands

A Study on the Characteristics of the Energy Performance in Curtain Wall Building - Focused on the Glazing Type, Window to Wall Ratio and Internal Gains -

A Study on the Characteristics of the Energy Performance in Curtain Wall Building - Focused on the Glazing Type, Window to Wall Ratio and Internal Gains -

An experimental study of air flow and temperature distribution in a room with displacement ventilation and a chilled ceiling

Displacement ventilation and chilled ceiling panel systems are potentially more energy efficient than conventional air conditioning systems and are characterized by the presence of vertical temperature gradients and significant radiant asymmetry. The characteristics of this type of system have been studied by making temperature and air flow measurements in a test chamber over a range of operating parameters typical of office applications. Results from the displacement ventilation study are consistent with other studies and show that normalized temperature profiles are independent of internal heat gain. Linear temperature gradients in the lower part of the room were found, in all cases, to be driven by convection from the adjacent walls. Significant mixing, indicated by reduced temperature gradients, was evident in the upper part of the room in the chilled ceiling results at higher levels of heat gain. Visualization experiments, velocity measurements and related numerical studies indicated that with greater heat gains the plumes have sufficient momentum to drive flow across the ceiling surface and down the walls. The significance of forced, as opposed to natural convection, is also suggested by relatively low Richardson Number (Ri) values found near the ceiling. Furthermore, in cases with moderately high internal gains, comparison of the temperature gradients indicated that the effect of ceiling surface temperature on the degree of mixing and the magnitude of the temperature gradient were of secondary importance. These findings are in contrast to the view that it is natural convection at the ceiling that causes enhanced mixing.

The Effect of Solar Heating Gain on Energetic Thermal Consumption of Housing

The passive solar house is designed to prevent heat loss and to maximize thermal input from the sun. Our study focuses on the effect of solar and internal heat gain on energy consumption of a typical well insulated house. The degree day's method was used to determine the heat losses by transmission and ventilation according to international standards on thermal insulation of building (NBN B62-301). It was found that the results of the study are very interesting and promising. By including the solar and internal gains, varied from 900 to 1400 kWh, it was indicated that the energy consumption decreased significantly. The thermal load for heat reached 60 kWh, but by including the free thermal gains, 10 kWh of energy was saved per day.

Solar blind metal-semiconductor-metal ultraviolet photodetectors using quasi-alloy of BGaN/GaN superlattices

Large internal gains that can be obtained in wide band gap semiconductors-based (GaN and ZnO types) Schottky and/or metal-semiconductor-metal photodetectors are generally accompanied by large dark current and time response. We show that, using quasi-alloy of BGaN/GaN superlattices as the active layer, the dark current can be lowered while maintaining high internal gain (up to 3 × 104) for optical power in the nW range and low time response (few tens of ns) for optical power in the W range. Furthermore, the boron incorporation allows the tuning of the cutoff wavelength.

Tellurium dioxide Erbium doped planar rib waveguide amplifiers with net gain and 28dB/cm internal gain

We report for the first time Erbium doped Tellurium dioxide single-mode planar rib waveguide amplifiers with net fiber to fiber gain and wide bandwidth operation. Peak internal gains of up to 14 dB have been achieved in 5 cm long rib waveguides (2.8 dB/cm) fabricated by co-sputtering of Tellurium and Erbium in an oxygen ambient and reactive ion etching.

High responsivity and internal gain mechanisms in Au-ZnMgO Schottky photodiodes

Schottky photodiodes based on Au-ZnMgO/sapphire are demonstrated covering the spectral region from 3.35 to 3.48 eV, with UV/VIS rejection ratios up to ∼105 and responsivities as high as 185 A/W. Both the rejection ratio and the responsivity are shown to be largely enhanced by the presence of an internal gain mechanism, by which the compensated films become highly conductive as a result of illumination. This causes a large increase in the tunnel current through the Schottky barrier, yielding internal gains that are a function of the incident photon flux.

Infrared luminescence and amplification properties of Bi-doped GeO2−Ga2O3−Al2O3 glasses

Bi, Ga, and Al codoped germanium glass was prepared and its optical properties were investigated by absorption, photoluminescence excitation (PLE), and photoluminescence spectra. Two active centers which occupy strong and weak crystal field environment are identified by using the PLE spectrum. The tunable and ultrabroadband luminescence properties are originated from electron transitions of these two active centers. Internal optical gain around 1300 and 1560 nm has been detected. The wavelength-dependent internal gains excited with 808 and 980 nm laser diodes show different characteristics, and the relative flat optical amplification can be realized by choosing 980 nm pumping.

MSFIA system for mercury determination by cold vapour technique with atomic fluorescence detection

A new multisyringe flow injection analysis system for mercury determination using cold vapour technique assembling with atomic fluorescence spectrometry is proposed. The system consists of a multisyringe module as liquid driver, a gas–liquid separator, a gas dryer device and an atomic fluorescence detector. As reducing agent, 1% tin chloride solution is used. Standard solutions and carrier are prepared in 1% hydrochloric acid. An argon stream is employed as carrier gas for cold vapour technique. The development of the smart analytical system is feasible due to the four internal gains of the atomic detector and the versatility of software used. According to the signal obtained, the software is able to choose the most suitable internal gain for sample analysis. Four linear calibration curves (i.e. one for each internal gain) were obtained. The smart system developed allows to determine a wide concentration range from 120 to 0.006 μg L −1 Hg. The detection limit (3 σ/ S) achieved is 0.002 μg L −1. The relative standard deviation is inferior to 2% for each calibration curve. This system was validated by means of a solid reference material and it was applied to environmental samples successfully.

Sensitivity analysis of a maritime located night ventilated library building

An examination of the role of design and operational parameters in a night ventilated library building located in Ireland, and which is subject to a maritime type climate, is considered. For this investigation, a self-contained space within the library building is analysed. A dynamic model of the space is created using the ESPr simulation package, which is compared with building data obtained from an experimental monitoring programme. Calculation of the mean bias deviation between the predicted and experimental data indicates agreement better than 0.45 °C for the dry bulb temperature and 1.1 °C for the mean radiant temperature. Using ESPr predictions, the role of different building design and operational parameters are examined by means of parametric analysis including building mass, ventilation duration, internal gain and ventilation rates. Compared to a reference base of the existing building, increasing the building mass was found to achieve a significant reduction in internal dry resultant temperatures, with a decrease of between 2 and 3 °C observed when mass was increased from 800 kg/m 2 to 1600 kg/m 2. Reducing building internal gains from 40 W/m 2 to 20 W/m 2 was observed to have the potential of further reducing dry resultant temperatures by up to 1 °C. Examination of night ventilation rates indicated that increasing night ventilation up to 10 ACH was observed to have a significant affect on reduction of dry resultant temperature, but further increases of air changes were observed to have a negligible effect.

Risk-Free Internal Gains -- Black and Scholes Re-Examined

In this paper, we first show that if a not-necessarily-self-financing portfolio has instantaneously riskless internal gains, then on an infinitesimal time-interval, the increase in the internal gains on the portfolio is the same as the change in the price of that amount of bonds which has the same wealth as the portfolio has. Then, using this result, we re-examine the original derivation of the Black-Scholes formula, and conclude that contrary to common belief, the argument of Black and Scholes can be made completely rigorous, employing the same delta-hedge portfolio that they used and keeping all their mathematical formulas; but the explanations they gave to support their formulas must be replaced by others.