FEM thermal performance analysis of multi-layer external walls during typical summer conditions considering high intensity passive cooling

Hudobivnik, Blaž; Pajek, Luka; Kunič, Roman; Košir, Mitja

doi:10.1016/j.apenergy.2016.06.036

Cited by 36 publications

(11 citation statements)

References 23 publications

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“…According to Serghides et al [8], high thermal resistance combined with thermal capacity seems to be the right measures to achieve this goal. Hudobivnik et al [33] observed that efficient thermal insulation prevents excessive energy conduction into the space on very hot days and massive layer acts as a heat sink thermally coupled with the space.…”

Section: Discussionmentioning

confidence: 99%

On the Role of External Walls in the Reduction of Energy Demand and the Mitigation of Human Thermal Discomfort

Kisilewicz

2019

Sustainability

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The structure and thermal properties of external walls affect both the thermal conditions inside the building and the energy demand. This applies to the energy requirement for heating as well as cooling. While the relationship between thermal insulation and heating is well-known, the effect of thermal insulation on overheating is not evident. One can find opinions that thick thermal insulation creates a “thermos effect” and significantly deteriorates the comfort conditions during the summer. In order to prove these statements, an office room with south-oriented glazing and a high thermal load from equipment was simulated by means of the Energy Plus program. The reference variant was a two-layer wall made from ceramic blocks and a 10 cm layer of thermal insulation. The duration of overheating in the investigated intensively used office space without window shading was approximately 26 to 29 days per year, depending on the expected comfort acceptance range, while in the case of the not insulated wall, it would be shorter by over 3 days. Increasing the thickness of the thermal insulation layer by up to 30 cm extended the overheating period by 4% to 9%. In relation to the whole simulation period, covering four summer months, this means approximately two extra days of discomfort. The effects of various passive methods of protecting buildings against overheating were also investigated. The use of night ventilation in this facility enables reducing the unfavorable conditions by as much as 31%, or up to 46% of the initial period of overheating. The change of the thermal inertia of a building by replacing the ceramic layer with heavy structural concrete allows a further reduction of the overheating duration by 8% to 9%. When the most effective ways of overheating protection are applied, such as night cooling, even a significant thickening of insulation no longer has any impact on its duration. The results shown above are obviously related to the adopted assumptions. However, on the basis of the conducted analyses, it is possible to reduce concerns relating to excessive insulating the building with respect to overheating. Having an optimal window area with nighttime cooling of buildings, window shading, and the inertial benefits associated with a massive construction are the most important and effective measures of protection against overheating. Efficient thermal insulation of the walls does not conflict with the thermal comfort conditions.

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Section: Discussionmentioning

confidence: 99%

On the Role of External Walls in the Reduction of Energy Demand and the Mitigation of Human Thermal Discomfort

Kisilewicz

2019

Sustainability

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“…To provide optimal environmental conditions for individual users it is necessary to pay attention not only to efficient heating and cooling system, but also to the application of dynamic building envelope with controlled surface temperature (matrix, Table 1 ). It is also important to take into consideration the thermal capacity of building envelope parts [ 80 , 81 ] as well as environmental issues [ 82 , 83 ]. During a heating season, poorly insulated building envelope and the use of a conventional system cause lower surface temperatures.…”

Section: Discussionmentioning

confidence: 99%

User-Centred Healing-Oriented Conditions in the Design of Hospital Environments

Dovjak

Shukuya

Krainer³

2018

IJERPH

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Design approaches towards energy efficient hospitals often result in a deteriorated indoor environmental quality, adverse health and comfort outcomes, and is a public health concern. This research presents an advanced approach to the design of a hospital environment based on a stimulative paradigm of healing to achieve not only healthy but also comforting conditions. A hospital room for severely burn patient was considered as one of the most demanding spaces. The healing environment was designed as a multi-levelled, dynamic process including the characteristics of users, building and systems. The developed integral user-centred cyber-physical system (UCCPS) was tested in a test room and compared to the conventional system. The thermodynamic responses of burn patients, health care worker and visitor were simulated by using modified human body exergy models. In a healing environment, UCCPS enables optimal thermal balance, individually regulated according to the user specifics. For burn patient it creates optimal healing-oriented conditions with the lowest possible human body exergy consumption (hbExC), lower metabolic thermal exergy, lower sweat exhalation, evaporation, lower radiation and convection. For healthcare workers and visitors, thermally comfortable conditions are attained with minimal hbExC and neutral thermal load on their bodies. The information on this is an aid in integral hospital design, especially for future extensive renovations and environmental health actions.

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“…The absorptivity (α) of the external façade rendering was in both instances presumed to be 0.4 (Table 3), corresponding to a light-coloured surface like beige, cream, sand, etc. [31]. The energy plus weather (EPW) climate data for Punat was prepared using a web weather [32].…”

Section: Methodsmentioning

confidence: 99%

Indirect green façade as an overheating prevention measure

2020

JCE

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Indirect green façade as an overheating prevention measure Simulation and experimental investigation of the indirect green façade (IGF) impact on thermal behaviour of buildings is presented in the paper. The study was conducted in Punat, Krk, Croatia, in the summer of 2018. The IGF reduced the incident solar radiation by up to 505 W/m 2 and façade temperatures by up to 13.5 K. Experimental results were used to simulate the indoor thermal comfort of a simple building model. When IGF was positioned across the entire sun-exposed wall, an average decrease of operative temperature was up to 6 K for a new house and up to 5 K for a traditional stone house.

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FEM thermal performance analysis of multi-layer external walls during typical summer conditions considering high intensity passive cooling

Cited by 36 publications

References 23 publications

On the Role of External Walls in the Reduction of Energy Demand and the Mitigation of Human Thermal Discomfort

On the Role of External Walls in the Reduction of Energy Demand and the Mitigation of Human Thermal Discomfort

User-Centred Healing-Oriented Conditions in the Design of Hospital Environments

Indirect green façade as an overheating prevention measure

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