Parameters of the carslaw-jaeger equation describing the temperature distribution in the ground

Larwa, Barbara; Gwadera, Monika; Kicińska, Izabela; Kupiec, Krzysztof

doi:10.4467/2353737xct.18.132.8971

Cited by 2 publications

(2 citation statements)

References 8 publications

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“…It can be estimated in several ways presented in recent decades by various authors. Carslaw and Jaeger [76] derived the equation of ground temperature at the given depth as a solution of the solution of the heat conduction equation in a semi-infinite medium under several assumptions [77][78][79]:…”

Section: Ground Temperaturementioning

confidence: 99%

Hourly Simulation of an Earth-to-Air Heat Exchanger in a Low-Energy Residential Building

Michalak

2022

Energies

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The earth-to-air heat exchanger (EAHE) is a well-founded and verified solution used in modern buildings both for heating and cooling purposes around the world. However, there is a lack of studies on operation of such devices cooperating with ventilation systems of buildings in hourly time step. In this study, the 5R1C thermal network model of a building from EN ISO 13790 was coupled with the EAHE model from EN 16798-5-1 to calculate hourly outlet air temperature. To improve the effectiveness of the considered solution, an additional algorithm was developed to choose between the EAHE outlet and ambient air as the source of ventilation air. Simulations were conducted in a spreadsheet for a low-energy single-family building. Ground temperature was compared with measurements taken in the considered location. The application of the EAHE with the proposed bypass resulted in a decrease in annual energy use for space heating and cooling from 14.82 GJ and 1.67 GJ to 12.74 GJ and 0.93 GJ, i.e., by 14% and 44%, respectively. Peak hourly heating and cooling thermal power decreased from 2.73 kW and 3.06 kW to 2.21 kW and 2.34 kW. Introduction of a bypass and switching between the EAHE and ambient air as the source of ventilation for the building resulted in annual energy savings of 123 kWh.

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Section: Ground Temperaturementioning

confidence: 99%

Hourly Simulation of an Earth-to-Air Heat Exchanger in a Low-Energy Residential Building

Michalak

2022

Energies

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“…For this purpose, the method given in EN 16798-5-1 was used. Simplification assumptions of that model were given and discussed in [35,[53][54][55]. The most important are as follows:…”

Section: Earth-to-air Heat Exchangermentioning

confidence: 99%

Impact of Air Density Variation on a Simulated Earth-to-Air Heat Exchanger’s Performance

Michalak

2022

Energies

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Due to their simple design and reliable operation, earth-to-air heat exchangers (EAHE) are used in modern buildings to reduce ventilation heat losses. EAHE operation in atmospheric conditions results in variation in ambient air temperature and pressure affecting air density. The paper presents the study on the impact of ambient air density variation on the calculated hourly air temperature at the EAHE outlet and the resulting energy use for space heating and cooling of an exemplary residential building. The ground temperature was computed from the model given in EN 16798-5-1. Then, air density was obtained using five various methods. Energy use for space heating and cooling of the building was computed using the 5R1C thermal network model of EN ISO 13790. Depending on the chosen method and concerning the base case without EAHE, a reduction in annual heating and cooling needs was obtained from 7.5% to 8.8% in heating and from 15.3% to 19% in cooling. Annual heating and cooling gain from EAHE were 600.9 kWh and 628.3 kWh for heating and 616.9 kWh and 603.5 kWh forcooling for the Typical Meteorological Years (TMY) and International Weather for Energy Calculation (IWEC) files, respectively. Unit heating and cooling gains per heat exchanger area were from 34.9 kWh/m2 to 36.8 kWh/m2 and from −35.1 kWh/m2 to −36.3 kWh/m2. Density variation with temperature from the relevant typical Polish meteorological year at constant pressure, in comparison to the method of EN 16798-5-1, resulted in an hourly difference of that unit gain up to 4.3 W/m2 and 2.0 W/m2 for heating and cooling, respectively. The same was true inthe case of IWEC files that resulted in differences of 5.5 W/m2 and 1.1 W/m2.

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Parameters of the carslaw-jaeger equation describing the temperature distribution in the ground

Cited by 2 publications

References 8 publications

Hourly Simulation of an Earth-to-Air Heat Exchanger in a Low-Energy Residential Building

Hourly Simulation of an Earth-to-Air Heat Exchanger in a Low-Energy Residential Building

Impact of Air Density Variation on a Simulated Earth-to-Air Heat Exchanger’s Performance

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