The use of energy in the livestock sector will rise in the years to come due to the increasing demand for animal proteins from a word population that will reach 9.15 billion people before 2050. ...Livestock houses for intensive animal farming are characterized by high energy consumption due to climate control that is needed to guarantee animals’ welfare and to maximize their production. Currently, there are neither international standards calculation models nor commercial tools for the estimation of this energy consumption. To fill this gap, this paper presents a simulation model (based on a customization of the hourly model of ISO 13790) for the estimation of the energy consumption due to climate control of broiler houses. This model provides the energy consumption for heating, cooling and ventilation and the main indoor environmental parameters for the evaluation of the animals’ welfare. The model was validated comparing its outputs with a dataset obtained through a monitoring campaign carried out in a broiler house during a production cycle. This research has several practical application: it can increase the knowledge about energy consumption in the livestock sector and the model can be also a useful tool for agricultural engineers and farmers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The Recast of the EPBD (Energy Performance of Buildings) Directive from the 2010 introduced the definition of a “nearly zero energy building”, covering its energy needs from renewable sources. In ...energy efficient buildings the energy needs depend strongly on the running conditions. Thus, such objects require high quality calculation models where a more detailed, hourly calculation, is needed.
The paper presents the application of the simple hourly dynamic calculation method from EN ISO 13790 standard with the use of Matlab/Simulink package for the calculation of annual demand of the heating and cooling energy. The control strategy described in this standard was applied in Simulink. Simulations were performed for the ten different locations, two for each of five climatic zones of Poland. Results of calculations were compared with the values obtained with two other methods: EnergyPlus detailed simulation, as a reference method, and monthly method from EN ISO 13790. The validation tests were performed for ten different locations, two for each of five climatic zones of Poland. The presented Matlab/Simulink model showed good accuracy. More significant differences were obtained for the cooling needs calculated with the monthly method. This implies the need of a further more detailed investigation on this method in Polish conditions.
•The 5R1C thermal network model of residential building has been converted to state-space model.•Three different calculation methods of the thermal performance of the building were compared.•Presented model meet the requirements of accuracy and can be practically applied.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents differences in calculations of annual heating and cooling energy need performed by numerical dynamic simulations software IDA ICE and those carried out by the modification of ...simple hourly method from EN ISO 13790 EN ISO 13790, widely used for determining building energy need. A simple model of a nearly-zero energy building was created and all heat gains and set-points that could lead to a mismatch in initial or boundary conditions were analysed. The impact of those on the annual heating and cooling energy need was examined by adding and/or removing every single one of them. Boundary conditions in numerical dynamic simulations were set up to match those in simple hourly method. Such an approach enables evaluation of differences in results and definition of their origin. The comparison of results has shown that in most cases, annual energy need for heating and cooling calculated using numerical dynamic simulations software differs from that calculated using EN ISO 13790. Among the others, more detailed heat accumulation model of heat gains in building’s envelope in IDA ICE software was marked as the main reason. Fact that solar heat gains seem to be underestimated by EN ISO 13790 and differences in heat transfer towards ground contribute to the differences in results as well.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Thermal solar systems are interesting solutions to reduce CO 2 emissions and gradually promote the use of renewable sources. However, sizing such systems and analysing their behavior are still ...challenging issues, especially for the trade-off between useful solar energy maximization and stagnation risk minimization. The new EPB (Energy Performance of Buildings) standard EN 15316-4-3:2017 offers several methods to evaluate the performance of a forced circulation solar system. One of them is a dynamic hourly method that must be used together with EN 15316-5:2017 for the simulation of the stratified storage tank connected with the solar loop. In this work, such dynamic hourly method is extended to provide more realistic predictions. In particular, modeling of the pump operation due to solar fluid temperature exceeding a set threshold, or due to low temperature differential between solar field and storage tank, is introduced as an on–off control. The implemented code is applied to a case study of solar system for the preparation of domestic hot water and the impact of different design parameters is evaluated. The model predicts a higher risk of overtemperature lock-out or stagnation when the solar field surface is increased, the storage volume is reduced and water consumption is set to zero to simulate summer vacation periods. Finally, a simple modulating control with a time step of a few seconds to a few minutes is introduced, quantitatively showing the resulting benefits in terms of useful solar energy increase, back-up operation savings and reduced auxiliary energy use.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this paper the new dynamic method for calculation of energy for heating, cooling and mechanical ventilation is presented. The method is based on a combination of the simple hourly method, from EN ...ISO 13790, and a modification of the existing calculation procedure for determination of the energy need for mechanical ventilation, described in Algorithm for calculation of the energy need for HVAC systems. Developed method, incorporated in Croa-tian national Algorithms used for energy certification of buildings, enables the determination of the hourly energy need for heating and cooling which includes all energy flows that occur during the air conditioning process (moistening, dehumidifying, etc.). Simulations are performed for a Croatian reference dwelling, equipped with two different HVAC systems. The results are compared against those obtained from the quasi-steady state monthly method, also described in Algorithms. The comparison proved that the application of the quasi-steady state method would preclude the correct calculations in buildings with air conditioning.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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