scholarly journals Energy Efficiency of a Solar Wall with Transparent Insulation in Polish Climatic Conditions

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 859
Author(s):  
Jadwiga Świrska-Perkowska ◽  
Andrzej Kucharczyk ◽  
Jerzy Wyrwał

A numerical model of a solar wall (SW) with transparent insulation (TI) is proposed in this article. The model is based on the finite-difference method and thermal conductivity equation, with a heat source term for the absorber. Using this model, the energy efficiency of a solar wall with transparent insulation (SW-TI) with honeycomb insulation made of modified cellulose acetate was analyzed in the case of different climatic conditions prevailing in Poland, different orientations of the envelope, and different insulation thicknesses. Simulations were carried out throughout the whole heating period. Monthly energy balances and temperature distributions for the analyzed envelopes at individual moments of the heating period are the basic results of the simulations. It was found that the use of 108 and 88 mm thick insulation was the most recommended in the considered temperate climate. Placing transparent insulation on a wall with an eastern or western orientation caused the annual heat balance of the envelope to decrease by 24–31% in relation to the value of this balance in the case of a southern orientation. The monthly heat balances obtained using the proposed model give results consistent with the method of calculating heat gains for opaque building envelopes with transparent insulation included in the PN-EN ISO 13790:2008 standard.

2018 ◽  
Vol 174 ◽  
pp. 01013 ◽  
Author(s):  
Jadwiga Świrska-Perkowska ◽  
Karolina Jęglet

This paper presents a numerical model of an accumulating solar wall with transparent insulation (ASW-TI). The objective of the simulation was to evaluate the energy efficiency of ASW-TI for different climatic conditions in Poland, i.e. for high, medium, and low irradiation. For each climate, the calculations were made for the entire heating period. As a result, temperature distributions in a wall at different times of the process and the energy balance of the wall in particular months and during the entire heating period were obtained.


Author(s):  
V. G Isakov ◽  
A. A. Abramova ◽  
M. Yu. Dyagelev

The authors proposed a model for estimating the heat balance and energy efficiency of a bioreactor that makes possible for a small-sized reactor operating on a relatively low-energy substrate to determine the critical volume, under which the existing climatic conditions allow year-round fully autonomous operation of the digester, as well as for evaluation the potential energy efficiency of such a bioreactor (output commodity heat). For the numerical characteristics of the climatic zone, it is proposed to use the average annual temperature and/or the “degree-day of the heating period” (DDHP) indicator common in construction heat engineering; the DDHP value more adequately characterizing the unevenness of the average monthly temperature distribution, i.e. degree of climate continentality. At the same time, the value of the critical volume of the bioreactor, at which year-round autonomous operation of the digester operating on the municipal sewage sludge, is possible, varies from 7.5 (Vladikavkaz, DDHP = 3410) to 17.0 m3 (Tomsk, DDHP = 6938), i. e. increases almost in proportion to the degree-day of the heating period. It should be noted that when using a substrate with a high biogas yield, e. g., pig manure (a biogas yield of 40 g/kg is adopted), the critical volume in all cases is less than 1 m3. Such results are relevant only for relatively low-energy raw materials. The nature of changes in the output of commodity heat, depending on the volume of the bioreactor and climatic conditions, is quite expectable, viz. the amount of heat that is useful for business interests is higher, the higher is the reactor volume and the milder is the climate. However, when the reactor volume is less than 5 m3, the non-linearity of the graphs is much higher, i. e. for a designer of especially small bioreactors, it seems mandatory to carry out such calculations. The obtained numerical values can be useful both for the designer of bioreactors and for the customer of the project when evaluating the economic efficiency of the planned new innovations.


2019 ◽  
Vol 11 (15) ◽  
pp. 4040 ◽  
Author(s):  
Gabriela Reus-Netto ◽  
Pilar Mercader-Moyano ◽  
Jorge D. Czajkowski

Energy ratings and minimum requirements for thermal envelopes and heating and air conditioning systems emerged as tools to minimize energy consumption and greenhouse gas emissions, improve energy efficiency and promote greater transparency with regard to energy use in buildings. In Latin America, not all countries have building energy efficiency regulations, many of them are voluntary and more than 80% of the existing initiatives are simplified methods and are centered in energy demand analysis and the compliance of admissible values for different indicators. However, the application of these tools, even when simplified, is reduced. The main objective is the development of a simplified calculation method for the estimation of the energy consumption of multifamily housing buildings. To do this, an energy model was created based on the real use and occupation of a reference building, its thermal envelope and its thermal system’s performance. This model was simulated for 42 locations, characterized by their climatic conditions, whilst also considering the thermal transmittance fulfilment. The correlation between energy consumption and the climatic conditions is the base of the proposed method. The input data are seven climatic characteristics. Due to the sociocultural context of Latin America, the proposed method is estimated to have more possible acceptance and applications than other more complex methods, increasing the rate of buildings with an energy assessment. The results have demonstrated a high reliability in the prediction of the statistical models created, as the determination coefficient (R2) is nearly 1 for cooling and heating consumption.


2014 ◽  
Vol 29 (2) ◽  
pp. 322-331 ◽  
Author(s):  
Anders Karlström ◽  
Karin Eriksson

Abstract This is the first in a series of papers presenting the development of a comprehensive multiscale model with focus on fiber energy efficiency in thermo mechanical pulp processes. The fiber energy efficiency is related to the defibration and fibrillation work obtained when fibers and fiber bundles interact with the refining bars. The fiber energy efficiency differs from the total refining energy efficiency which includes the thermodynamical work as well. Extracting defibration and fibrillation work along the radius in the refining zone gives information valuable for fiber development studies.Models for this process must handle physical variables as well as machine specific parameters at different scales. To span the material and energy balances, spatial measurements from the refining zone must be available. In this paper, measurements of temperature profile and plate gaps from a full-scale CD-refiner are considered as model inputs together with a number of process variables. This enables the distributed consistency in the refining zone as well as the split of the total work between the flat zone and the CD-zone to be derived. As the temperature profile and the plate gap are available in the flat zone and the CD-zone at different process conditions it is also shown that the distributed pulp dynamic viscosity can be obtained. This is normally unknown in refining processes but certainly useful for all fluid dynamic models describing the bar-to-fiber interactions. Finally, it is shown that the inclusion of the machine parameters will be vital to get good estimates of the refining conditions and especially the split between the thermodynamical work and the defibration/fibrillation work.


Author(s):  
Martina Caruso ◽  
Rui Pinho ◽  
Federica Bianchi ◽  
Francesco Cavalieri ◽  
Maria Teresa Lemmo

AbstractA life cycle framework for a new integrated classification system for buildings and the identification of renovation strategies that lead to an optimal balance between reduction of seismic vulnerability and increase of energy efficiency, considering both economic losses and environmental impacts, is discussed through a parametric application to an exemplificative case-study building. Such framework accounts for the economic and environmental contributions of initial construction, operational energy consumption, earthquake-induced damage repair activities, retrofitting interventions, and demolition. One-off and annual monetary expenses and environmental impacts through the building life cycle are suggested as meaningful performance metrics to develop an integrated classification system for buildings and to identify the optimal renovation strategy leading to a combined reduction of economic and environmental impacts, depending on the climatic conditions and the seismic hazard at the site of interest. The illustrative application of the framework to an existing school building is then carried out, investigating alternative retrofitting solutions, including either sole structural retrofitting options or sole energy refurbishments, as well as integrated strategies that target both objectives, with a view to demonstrate its practicality and to explore its ensuing results. The influence of seismic hazard and climatic conditions is quantitatively investigated, by assuming the building to be located into different geographic locations.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4440
Author(s):  
Bader Alshuraiaan

The purpose of this study is to identify the most relevant renewable energy technologies for buildings and to assess the effectiveness of their implementation in the long term for Kuwait. Methods of analogies and comparisons were used to determine the features of energy efficiency based on the technologies under study. The study proposes the methodological approach to assessing the effectiveness of the introduction of renewable energy technologies, determining the direction of increasing the energy efficiency of buildings and the investment efficiency of introducing these technologies. Renewable energy efficiency analysis for buildings in Kuwait confirms that solar energy systems have been the most widely available for widespread use of solar energy over the past three years. An increasing level of energy efficiency with a decrease in the notional cost of increasing energy savings is characteristic of solar collectors with booster reflectors. The proposed model for assessing the level of energy saving provides an opportunity for economic justification of introducing renewable energy technology in buildings.


2020 ◽  
pp. 105-109
Author(s):  
Alexander T. Dvoretsky ◽  
Oleg V. Sergeichuk ◽  
Alexander V. Spiridonov

For insolation calculations and design of shading devices (SD) comprising plane sections or fins, the method based on solar maps shall be preferred because of its high descriptiveness and universality.The article describes the algorithm of design of a general-position SD using a solar map and a shade clinometer. An example of calculation of SD geometry parameters such as fin slopes with the horizontal plane and the facade plane, distance between the fins with consideration of screening of the translucent structure during the building cooling period and of transmission of solar radiation during its heating period is given in the article. A simplified formula of a general-position SD energy efficiency calculation is proposed.


2021 ◽  
Vol 14 (2) ◽  
pp. 124-131
Author(s):  
K. A. Ignatiev ◽  
E. R. Giniyatullin ◽  
M. G. Ziganshin

Combined air and water heating schemes have been actively used recently for heating public and residential premises. They have certain advantages in countries with a warm climate, whereas in a temperate climate, their use may be unfeasible. The most effective regulation of the heating system in the building can be expected, if all the technology specifics are taken into account, in terms of both the purpose of the room and the methods of regulation. A system focused only on weather-based regulation falls short of meeting to energy-efficient control classes: a heat carrier with the same temperature is distributed among rooms with different requirements for temperature and humidity characteristics. The issues of ensuring the energy efficiency of the combined air and water heating system in public buildings for the temperate continental climate of Russia — the academic building (AB) and laboratory building (LB) of the Kazan State Energy University (KSEU) have been considered. Heating devices of the KSEU heating system have manual control valves installed in the premises, or radiator valves with thermostatic heads, but without room controllers, which does not meet the energy-efficient control classes. An experimental survey of the functioning of the heating system of the KSEU buildings during the 2019 – 2020 and 2020 – 2021 heating seasons was conducted. The optical pyrometry method was used to measure the temperature of the surfaces of windows, walls and elements of the heating system, as well as the temperature and humidity of the air in lecture rooms and corridors of the AB and LB of the KSEU. The parameters of heating devices and indoor air in rooms of various purposes were found compliant with the current sanitary and hygienic requirements. At the same time, the need to switch to a higher class of regulation has been revealed, since, under the current situation, the parameters of the indoor air depend on the outdoor temperature: in the abnormally warm winter of 2020, the indoor air temperature was at the edge of the maximum permissible value, while in the normal climate of winter of 2021, it was at the edge of the minimum permissible value.


2018 ◽  
Vol 7 (2.17) ◽  
pp. 70
Author(s):  
Jaiganesh K ◽  
Karuppiah N ◽  
Ravivarman S ◽  
Md Asif

The maximum electrical energy conversion efficiency of the Solar PV panel is up to 22% in normal conventional roof- top system under the temperature of 25˚C on Standard Test Condition (STC). In Indian climatic conditions, the atmospheric temperature is mostly above 35˚C to 45˚C, it incites 35˚C to 80˚C temperature on the PV panel. The black body of the PV panel absorbs more heat. This temperature affects the electrical efficiency of the panel significantly. This paper proposes the mathematical modelling of the solar PV panel for different solar irradiation and the temperature. The experimental evaluation is conducted in the latitude of 11.36 (N) and longitude 77.82 (E). The testing and monitoring was done with LabVIEW based National Instruments hardware such as NI cDAQ-9178, NI DAQ - 9227 and NI DAQ 9225. The comparative study between the simulated result and real time hardware results are discussed in this paper. The test result shows that the output of the proposed model mismatches with the experimental output of the solar PV panel due to the negative correlation between the efficiency and temperature for variable irradiation condition. It shows a power difference of 9.41W between the output of the proposed model and the experimental setup.  


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