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1

A review of energy saving and energy effective roofings

100%

Savchenko O.

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tom Z. 27 (177)

219-224

EN

This article is a systematic review of the literature on the energy efficiency and energy efficient construction of roofs. This paper considers seven types of roof, including insulated, double-skin, cool roofs, green roofs, roofs with photovoltaic panels, biosolar roof and roof ponds. The review covers the main characteristics of each roof, the reduction of heat flux and the appropriate climate for its implementation. These roofs can reduce energy consumption for cooling or heating systems. For the cold period of the year the warmed roof which reduced heat losses of the room to 70% proved to be the most effective. In hot climates the cool roof is the simplest covering, which reduces the flow of solar radiation into the room by 30%. The installation of a double-skin roof or a pond on the roof stabilizes the temperature in the room on hot days. Green roofs in hot climates can reduce the heat of solar radiation through the roof to 35%, and the presence of photovoltaic panels on the green roof can increase their efficiency by 8.3%. To increase the energy efficiency of the roof, it is advisable to combine several types of roofs.

PL

Artykuł stanowi przegląd literatury dotyczącej energooszczędnych rozwiązań konstrukcji dachów. W artykule omówiono siedem rozwiązań dachów, w tym dach izolowany, dach o podwójnej konstrukcji, dach chłodzony, dach zielony, dach z panelami fotowoltaicznymi, dach biosolarny i taras. Przegląd zawiera charakterystykę każdego dachu, redukcję strumienia ciepła oraz wskazuje warunki klimatyczne odpowiednie do zastosowania takiego rozwiązania. Zastosowanie odpowiednich rozwiązań może zmniejszy zużycie energii na chłodzenie lub ogrzewanie. W okresie zimowym najkorzystniejszy okazał się dach ocieplony, który pozwala na zmniejszenie strat ciepła do 70%. W klimacie gorącym najlepszym rozwiązaniem jest powłoka chłodząca, która ogranicza dopływ promieniowania słonecznego do pomieszczenia o 30%. Zastosowanie dachu podwójnego lub tarasu pozwala na stabilizację temperatury w pomieszczeniu w upalne dni. Zielone dachy w gorącym klimacie mogą zmniejszyć ciepło promieniowania słonecznego przez dach do 35%, a obecność paneli fotowoltaicznych może podnieść ich wydajność o 8,3%. Aby zwiększyć efektywność energetyczną dachu, zaleca się łączenie kilku rodzajów dachów.

2

Analysis of air jets velocity attenuation at special initial conditions

38%

Voznyak O. , Spodyniuk N. , Savchenko O. , Dovbush O. , Kasynets M. , Datsko O.

Diagnostyka

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2022

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tom Vol. 23, No. 3

art. no 2022308

EN

The article is devoted to solving the significant problem of efficiency increasing of air distribution in the premise by swirl air jet. The aim of the article is to decrease coefficient of velocity attenuation due to intensification of initial turbulence of different air streams leakage from the air distributor and to obtain of analytical equations for calculation of air distribution in a room to ensure the normative indoor air parameters. Effect of flow twisting results in a reduction of the velocity attenuation coefficient by 2.4 times. The regression analysis testified that the attenuation coefficient of the swirl air jet is more affected by the angle of the twisting plates inclination and less affected by the angle of change of the air flow direction. The attenuation coefficient of all types of rectangular air jets is more influenced by the the ratio of the sides of slit b/l and the angle of change of the air flow direction is also less affected. To minimize the attenuation factor, it is effective to use air distributors at smaller swivel plates inclination angles for swirl air jets and a smaller slit size ratio for all types of rectangular air jets.

3

Analysis of premise infrared heating and ventilation with an exhaust outlet and flat decking air flow

38%

Voznyak O. , Spodyniuk N. , Savchenko O. , Dovbush O. , Kasynets M. , Datsko O.

Diagnostyka

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2022

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tom Vol. 23, No. 2

art. no. 2022207

EN

The article is devoted to solving of urgent problem to analyse energy saving effect from radiant heating and ventilation of premise with exhaust outlet and flat decking air jet. The aim of the work is analysis of energy efficiency of radiant heating systems using infrared heaters and ventilation of the premise due to the effect of a flat decking air jet on the surface of the heater; determination the amount of heat received both by flat decking air jet from the infrared heater when laying on its flat surface and amount of heat from the exhaust air entering the recuperator. Use of the infrared heaters in combination with an air distribution of the ventilation system with the flat decking air jets is effective, as it allows to achieve savings in heat load of the ventilation system in the range of 11%-19%. The amount of heat recovery of the exhaust air removed by the exhaust outlet is 30-40 W that equals 15%-20%. Saving the heat load of the ventilation system allows reducing the actual initial temperature of the tidal flat decking air jet and achieving a total saving of thermal energy of 24%-34%.