ZEMCH 2019 International Conference Proceedings April.2020 | Page 294
1.
Introduction
Energy provision through integrated active solar technologies would reduce substantially
residential consumptions; then combination with passive and energy efficiency strategies allow to
reach buildings with a neutral energy balance and surplus production [1, 2]. This work studies this
residential capability in the city of Concepción, such is located in the South Hemisphere close to the
Pacific Ocean (36°49S; 73°03W) with template seasonal climate. It is the central county of the main
metropolitan area in the south of Chile, with an estimated population of 230,729 inhabitants [3]. This
city is characterized by cold winters with an annual average temperature of 12.4 ºC, which generates
mostly energy demands for heating. In contradistinction to cities in the south of Europe with similar
latitude, like Seville (37°N,5.99W) or Barcelona (41°N,2°W), higher temperatures are observed (annual
average of 19.2 °C and 16.1 °C respectively) [4]. Also, a deficit in constructive quality of dwellings is
common in this context, which implies higher energy consumption [5–7]. Then, to achieve neutral
annual energy balance (Net‐Zero houses), implies larger solar capture areas (more than 0.6 m2 per m2
built area estimated in northern hemisphere) [8]. But, typical energy demands could be mitigated
through passive strategies [7,9]. Besides, to deploy larger solar collectors, become useless after
supplying the own demands, then surplus should feed for other uses and/or the urban grid [10,11], like
the approach regarded in Plus‐Energy homes [12]. As well as in the concept of Powerhouse, such
involves the full life cycle of buildings, including the construction process, a life expectancy of 60 years
of use and the demolition, regarding the required energy generated by on‐site renewables sources [13].
The overall integrated solar potential of buildings has been analysed previously in the same city
[14]; and extreme cases of houses by geometry of roofs to integrate collectors have been reviewed [8].
In this study, a single‐family dwelling model observed with highest solar potential in the previous
work is selected, because it shows also important capability of radiation capture in the front and back
façade with passive solar collection.
The active solar technologies considered are: Building Integrated Photovoltaic (BIPV) [15,16],
Building Integrated Solar Thermal with Liquid Fluid (BISTw) [17]; hybrid Building Integrated Solar
Thermal‐Photovoltaic, with Air as Thermal Fluid (BIPVTa) [1] and with liquid fluid (BIPVTw) [18–20].
To estimate the overall capability and thermal efficiency of these technologies, the F‐Chart tool is used
[21]. This tool is based on equations that predicts solar thermal capability with an error expected of
between 1.1% to 4.7% in relation to dynamic simulation methods, and up to 15% to real measurement
data [22]. To estimate the thermal efficiency in liquid fluid, the performance of Wunder CLS 1808 model
of Solimpeks@ product are adopted. This product has a coefficient of absorption η0 = 0.763 and thermal
loss a0 = 3.514 Wm‐2K‐1, with a collection surface of 1.23 m2 per unit. The technologies described and
their performance have been previously analysed in the local context [14, 23, 24]. The efficiency rates
and sizes of the solar panels has been used in a recent research [24]. The PV panels dimensions are 1660
mm x 830 mm x 45 mm; and electrical efficiency is 12% compared to available irradiation (considering
average efficiency of 16% and expected losses of 25%) [25]. The BIPVa hybrid has an estimated thermal
efficiency to three times the direct electrical efficiency [26,27]. An 8% is considered for electrical
efficiency with a hybrid collector, and the considered size of BISTw and BIPVTw collectors is 1660 mm
x 830 mm x 90 mm.
2.
Materials and Methods
Based on a register of Real Estate Developments in the city [8, 14, 24], a model is chosen due its
relevant possibilities for active and passive solar collection (Fig. 1 Left). The selected design has in back
side a larger roof sides with potential for solar capture; complementary to three windows that serve
two rooms and the living room, which can provide passive solar capture. Additionally, in the front
façade are the access, stairs, two bathrooms and only one room restricted from direct irradiation. Then,
the design is adapted with one room more in the second storey to get a regular roof geometry without
shadow and more capture of solar passive energy through one extra window (Fig.1 Right).
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ZEMCH 2019 International Conference l Seoul, Korea