Thermal and Optical Properties of the Sunspace Casing as Factors Influencing Temperature Rise in Greenhouse Systems

Abstract

In sunspaces, there is an observable temperature rise above the external air temperature, caused by solar gains and the buffering effect of their enclosure. In addition, their external partitions form a barrier preventing the direct influence of the external environment and delaying the natural deterioration of elevation surface. In the paper, the temperature rise in a glazed balcony attached to a typical flat in a multifamily building, together with the energy demand in the living zone, were assessed with the use of dynamic computer simulations. Ten variants of the sunspace casing were analysed, with different thermal and solar energy transmittance of the glazing (which is a novel subject in the research area). This enabled us to evaluate average values of the temperature reduction factor during the year and to choose the most efficient variant of the sunspace external partitions. It turned out to be an insulated, double-glazed casing with a spectrally selective coating (type O 21), combining high insulative properties with high solar transmittance. These features allowed the temperature in the sunspace to rise by almost 10°C (compared with the external air) and lower total energy demand in the flat by 33% (compared with a flat with an open balcony).

Energy Simulations of a Building Insulated with a Hemp-Lime Composite with Different Wall and Node Variants

“…The program was also validated in two ways by one of the authors: according to EN 15265 standard [43], and based on the measurements carried out in the climatic chambers of the Rzeszów University of Technology. The validation procedures were described in detail in [44][45][46].…”

Investigation of effective parameters the performance of attached sunspace in reducing energy consumption in a residential building: A study in Tabriz, Iran

“…Installing a solar greenhouse provides additional benefits beyond energy savings, such as enhancing the building's external appearance and offering renovation protection (Grudzinska, 2021). In cold climates, the use of double-glazed glass is recommended for solar greenhouse design, whereas locations with milder winters may suffice with singleglazed glass (Ma et al, 2020).…”

Evaluation of Building Energy Savings Achievable with an Attached Bioclimatic Greenhouse: Parametric Analysis and Solar Gain Control Techniques

“…The attached solar greenhouses, which are an open thermodynamic system with energy and mass exchange, receive heat from the sun's rays passing through the glass envelope [10]. The installation of a solar greenhouse also provides additional benefits, not related to energy savings, such as the renovation and weather protection of the building's exterior façade [11].…”

“…Ulpiani et al [8] found that in Italy, a greenhouse with convective heat exchange with double glazing and reduced depth reduced daily consumption more than 27%, highlighting how the use of a greenhouse with reduced depth leads to greater savings. Grudzinska [11] achieved energy demand savings of 33% by using a double-glazed envelope with selective coating in Poland. These articles do not investigate the performance using low-e double glazing.…”

“…The optical properties of the glazing greatly influence the behavior of the greenhouse; for proper functioning, the glass chosen should allow an adequate level of insulation without an excessive penalization of solar gain [11]. In sites with cold climates or harsh winters, the use of double glazing is advisable, as opposed to sites with mild winters, where single glazing is sufficient [13,19].…”