scholarly journals Thermal energy use for dehumidification of a tomato greenhouse by natural ventilation and a system with an air-to-air heat exchanger

2017 ◽  
Vol 26 (1) ◽  
pp. 56 ◽  
Author(s):  
Katarzyna Maslak ◽  
Sven Nimmermark
Keyword(s):  
Mechanical Ventilation ◽  
Heat Exchanger ◽  
Leaf Area Index ◽  
Thermal Energy ◽  
Natural Ventilation ◽  
Energy Use ◽  
Energy Savings ◽  
Moisture Removal ◽  
Area Index ◽  
Total Thermal Energy

The aim of the study was to estimate the amount of thermal energy used for dehumidification of a naturally ventilated tomato greenhouse and to estimate how mechanical ventilation with the use of a heat exchanger recovering heat from the exhaust to the supply air may decrease the energy use. Measured use of thermal energy in a naturally ventilated tomato greenhouse was compared to modelled values using Powersim® software. By the help of the model an estimation of the amount of energy used for dehumidification was made for the months April – September. A non-hygroscopic rotary air-to-air heat exchanger was studied, and its temperature and moisture efficiencies were measured. Modelling for leaf area index (LAI) 3.5 and 4.0 m2 m-2 indicated that 23 and 29% of the total thermal energy was used for moisture removal respectively. Modelling for the heat exchanger indicated thermal energy savings of 15 and 17% for the same LAI respectively.

scholarly journals Multi-Country Analysis on Energy Savings in Buildings by Means of a Micro-Solar Organic Rankine Cycle System: A Simulation Study

Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 119 ◽  
Author(s):  
Alessia Arteconi ◽  
Luca Del Zotto ◽  
Roberto Tascioni ◽  
Khamid Mahkamov ◽  
Chris Underwood ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Energy Demand ◽  
Energy Use ◽  
Energy Savings ◽  
Organic Rankine Cycle ◽  
Cost Savings ◽  
Rankine Cycle ◽  
Primary Energy ◽  
Operational Cost ◽  
The North

In this paper, the smart management of buildings energy use by means of an innovative renewable micro-cogeneration system is investigated. The system consists of a concentrated linear Fresnel reflectors solar field coupled with a phase change material thermal energy storage tank and a 2 kWe/18 kWth organic Rankine cycle (ORC) system. The microsolar ORC was designed to supply both electricity and thermal energy demand to residential dwellings to reduce their primary energy use. In this analysis, the achievable energy and operational cost savings through the proposed plant with respect to traditional technologies (i.e., condensing boilers and electricity grid) were assessed by means of simulations. The influence of the climate and latitude of the installation was taken into account to assess the performance and the potential of such system across Europe and specifically in Spain, Italy, France, Germany, U.K., and Sweden. Results show that the proposed plant can satisfy about 80% of the overall energy demand of a 100 m2 dwelling in southern Europe, while the energy demand coverage drops to 34% in the worst scenario in northern Europe. The corresponding operational cost savings amount to 87% for a dwelling in the south and at 33% for one in the north.

scholarly journals Simulation of Double Pipe Heat Exchanger with Implementation of PCM

2019 ◽  
Vol 8 (12) ◽  
pp. 658-663
Keyword(s):  
Heat Exchanger ◽  
Thermal Energy ◽  
Energy Use ◽  
Phase Change Materials ◽  
Time Step ◽  
Contour Plots ◽  
Materials Used ◽  
Double Pipe ◽  
Thermal Energy Storage Systems ◽  
Pipe Heat

In the present time several techniques have been developed in managing and storing thermal energy. Use of Thermal energy storage systems (TES) are one of the solutions for this issue. Hence in the present work, phase change materials (PCM) are used for storing thermal energy. D-mannitol and Hydroquinone are the two PCM materials used in double pipe heat exchanger and simulations are carried out analytically on ANSYS. Study of temperature variation is done with respect to time and values are calculated for time, t = 200, 500, 2200 and 4200 seconds. The results also include contour plots and numerical values for mass fraction for each of the case. The result shows, that with increase in the time step, the temperature gradually increases for both the cases of PCM materials.

scholarly journals Controlled Mechanical Ventilation in Buildings: A Comparison between Energy Use and Primary Energy among Twenty Different Devices

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2123 ◽  
Author(s):  
Lamberto Tronchin ◽  
Kristian Fabbri ◽  
Chiara Bertolli
Keyword(s):  
Mechanical Ventilation ◽  
Energy Consumption ◽  
Thermal Energy ◽  
High Performance ◽  
Energy Use ◽  
Operating Cost ◽  
Primary Energy ◽  
Energy Requirements ◽  
Controlled Mechanical Ventilation

Indoor air quality (IAQ) of buildings is a problem that affects both comfort for occupants and the energy consumption of the structure. Controlled mechanical ventilation systems (CMVs) make it possible to control the air exchange rate. When using CMV systems, it is interesting to investigate the relationship between the useful thermal energy requirements for ventilation and the energy consumption of these systems. This paper addresses whether there is a correlation between these two parameters. The methodology used in this work involves the application of equations of technical Italian regulations UNI/TS 11300 applied to a case study. The case study is represented by a 54 m3 room, which is assumed to have three CMV systems installed (extraction, insertion, insertion and extraction) for twenty different devices available on the market. Afterwards, simulations of useful thermal energy requirements QH,ve and primary energy EP,V were performed according to the electrical power of each fan W and the ventilation flow. The results show that the two values are not linearly correlated: it is not possible to clearly associate the operating cost for CMV systems according to building requirements. The study also shows that CMV systems are particularly efficient for high-performance buildings, where there is no leakage that can be ascribed to windows infiltrations.

Long-Term Assessment Methodology of Building Stock Thermal Energy Consumption

2021 ◽  
Author(s):  
◽  
Aleksejs Prozuments
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Thermal Energy ◽  
Energy Use ◽  
Energy Savings ◽  
Building Code ◽  
Space Heating ◽  
Industrial Building ◽  
Building Stock

Energy efficiency in the building stock is a substantial contributor to infrastructure sustainability. In Latvia, buildings’ thermal energy use for space heating accounts for 80 % of total building energy use in the cold season. Therefore, reducing thermal energy consumption for space heating needs through the implementation of energy efficiency measures, enforcement of local building codes and regulations can ultimately lead to cost savings for building owners and stakeholders. The present PhD Thesis introduces a methodology for evaluation of thermal energy saving potential in the long run across residential, public, and industrial building stock under various thermal energy consumption compliance scenarios. These scenarios were developed based on three different building code protocols with a 10-year forecast analysis. Evaluation of the proposed building code implementation practices and their feasibility in Latvian building stock is discussed for these buildings with regards to their long-term thermal energy savings potential.

Characterizing leaf area index of rooftop farm to assess thermal-energy performance by simulation

2021 ◽  
pp. 110960
Author(s):  
Eduardo Grala da Cunha ◽  
Celina Maria Brito Correa ◽  
Roberta Peil ◽  
Viviane Mülech Ritter ◽  
Daniela Hohn ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Thermal Energy ◽  
Energy Performance ◽  
Area Index

Toplotno bilansiranje i povećanje efikasnosti korišćenja toplotne energije vrtića „Zeka“ u gradu Kragujevcu, Srbija

2020 ◽  
Vol 22 (1-2) ◽  
pp. 119-125
Author(s):  
Davor Jovanović ◽  
◽  
Dušan Gordić ◽  
Jelena Nikolić ◽  
Nebojša Jurišević ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Thermal Energy ◽  
Energy Use ◽  
Energy Savings ◽  
Heating System ◽  
Transfer Coefficients ◽  
Climate Conditions ◽  
Heat Transfer Coefficients ◽  
Energy Conservation Measures

This paper shows the thermal energy audit of the kindergarten "Zeka", located in the territory of the city of Kragujevac, Serbia. Data of the analyzed building, with an emphasis on the heating system, as well as the climate conditions of the location are shown. Analysis of the thermal energy use, done by implementing a software package "URSA-građevinska fizika 2", shows that the analyzed building belongs to the "G" energy efficiency level, which indicates that the heat transfer coefficients are not in the range defined by the Rule book of energy efficiency for buildings. Consequently, the energy conservation measures for increasing the efficiency of thermal energy use are proposed. Besides, for each measure, the techno- economic analysis was done, which includes determination of the investment costs, as well as the payback period. By implementing the appropriate measures in the analyzed building, it was concluded that thermal energy savings of almost 79% can be achieved.

scholarly journals Energy Savings Resulting from Using a Near-Surface Earth-to-Air Heat Exchanger for Precooling in Hot Desert Climates

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8044
Author(s):  
Ali Pakari ◽  
Saud Ghani
Keyword(s):  
Heat Exchanger ◽  
Energy Use ◽  
Energy Savings ◽  
Field Measurements ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Environmental Benefits ◽  
Cooling Systems ◽  
Near Surface ◽  
Space Cooling

Given the substantial energy use for space cooling in buildings, integrating energy-efficient and sustainable cooling systems into buildings has become increasingly more important. Even though the cooling potential of a near-surface earth-to-air heat exchanger (EAHE) with grass cover was demonstrated in previous studies, the energy savings and environmental benefits resulting from using the EAHE have not yet been quantified. Therefore, in this study, we quantify the energy savings resulting from using a near-surface earth-to-air heat exchanger (EAHE) with grass-covered ground as a precooling unit in hot desert climates. The outlet air conditions of the EAHE during 9 months of the year (March to November), where space cooling is required, are predicted using a 3D transient CFD model, which is validated against field measurements. The EAHE is fabricated from a 1 mm thick aluminum tube with a diameter of 0.15 m and a length of 21.5 m, buried 0.4 m deep. The results showed that the EAHE can cool ambient air by up to 8.5 °C at an air flow rate of 607 m3/h, corresponding to a cooling capacity of 1700 W and a COP of 17. The daily average cooling capacity of the EAHE is about 560 W for an average operation period of 15.1 h per day. When used as a precooling unit for conventional cooling systems, the highest estimated monthly energy savings is 115 kWh, and the estimated annual savings is 741 kWh.

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