Assessing the thermal performance of a conventional architecture in a dry warm climate

In this article, we present the results of the evaluation of the thermal performance of a conventional home in a dry warm climate, a case study in Bucaramanga, Colombia. This simulation, evaluation, and analysis make it necessary since currently in the case study area there is no thermal assessment of the dwellings, which are old houses built with resistive and mechanical analyses, but without regard to thermal behavior or thermal housing comfort. This evaluation is done by means of software simulation. Thus, a valid simulation identifies the weather data present in a dry warm climate zone and determines the geographical location and behavior in the solar diagram. Likewise, the thermal characterization of the soil and the construction materials of support and envelopes of the architecture is performed, to establish its thermal transmittance, thermal resistance, and thermal capacity. As a result of the research, the thermal behavior of the house is presented by means of the calculations made that determine the thermal behavior of the envelopes, energy load balancing, and housing thermal comfort based on the ASHRAE 55 standard by Fanger's method. Consequently, with the above, the results of the simulation and a detailed analysis of the recorded data are presented in the document.


Preparation
Residential and commercial constructions in developed nations account for around 40% of total energy consumption, outperforming other major sectors such as industry and transportation [1], [2]. In 2019, primary energy use in Colombia's homes accounted for 20% of the country's total demand [3]. Obviously, the construction sector has a direct impact on society, the environment and the economy [4], [5].
Building design is not only an aesthetic form and concept [6],[7],[8], but also a holistic process that contains an accurate selection of structure materials that can diminish building energy consumption and the implementation of passive design strategies[9], [10], [11]. During their typical natural life of 50 ages or more [12], Contemporary buildings will be subject to a meteorological state that will be progressively hotter and more unstable [13], [14], [15].
From this point of view, it is imperative to understand the energy performance of buildings done precise energy and thermal analysis [16], [17]. The use of unconventional energies, the energy landscape, the likelihood of reviewing Regulations and Building Codes [18], the increase in the purchase of air conditioning equipment, the trend of increase in housing construction, among other causes, motivated different authors to assess residential buildings to examine thermal-energy behavior, comfort situation, energy use [19]- [24]. Therefore, to assess the thermal presentation and energy efficacy of buildings and buildings, numerous simulation programs are used globally that carry out these activities [25]- [28].
The objective of this study is to estimate the thermal behavior of a conventional house case study in dry warm climate, using DesignBuilder software, initiating by the climatic identification of the area [29], followed by the thermal-fisque characterization of soil materials and construction envelopes, in order to analyze according to the ASHRAE 55 standard [30] the parameters of comfort or discomfort present is housing.

Methodology
A thermal analysis of a case study house was carried out, by means of simulations in the current state of construction. This analysis aimed to determine the current thermal behavior of the case study house, which is a conventional house in dry warm climate, which is located in Bucaramanga, Santander, Colombia. The total area of the house is 126m2 and comprises two floors, each is divided into housing spaces of different sizes such as bedrooms, bathrooms kitchen and others.
For the study of the architecture to be evaluated, the method of validation in specialized software that allows the calculation of thermal loads is used [31], because, without a computational tool, the evaluative calculation by the large number of variables to be considered and iterations for its lowest error percentage is not feasible [32].
There are currently a wide diversity of computational tools for the study of thermal loads such as vpClima [33], CYPEcaD MEP [34], OpenStudio [35], Ecotect Software de Sustainable Construction Design [36], Energyplus [37], Designbuilder [38], among others. For this case study the methodology was based on the analysis of thermal-energy performance by simulation using Design Builder software.

Identification
Initially for the base case, the identification of building materials is carried out, with a total area of 126m2, comprising two floors. The first floor involves of a breathing room, a kitchen, a bedroom and a bathroom. For the second floor, you have access by stairs starting from the first floor giving way to two bedrooms and a bathroom. The present case study is a construction that used the traditional building material in Colombia as follows: the ceiling is made of wooden beams that support sheets of wood thickness of 1.9cm, with an elastomeric waterproofing envelope of 2cm supporting mud shingles type medium cane with thickness of 3cm (see Fig.  1). The floor layers in the area are composed of mixture of sand, gravel and stone, cement biker; 7cm cement fiber and ceramic as shown in Fig. 2a. Partition walls include plaster, brick and cement (Fig. 2b). The exterior walls are prefabricated concrete blocks composed of stucco [39], concrete and steel, and the exterior window is made of 6mm clear glass. In Table 1mentions

Simulation
The architecture is simulated based on the weather data present in dry warm climate and identification of the geographical location in which the case study is located [40] (See Figure 3 in addition to this is the thermal characterization of the enclosures that make up the construction structure of the house as shown in Table 2 .  The thermal performance assessment of conventional architecture in dry warm climate is complemented by the analysis of comfort and set point hours completed to determine the housing comfort of the home.

Results
The interior thermal performance of the house analyzes the thermal-physical properties of structural envelopes such as average climate behavior per hour in a day [41], to determine the internal gains of the case study (See Figure 4). Based on the weather data in which the architecture is exposed, gain data taking into account the thermal balance of the influential factors, the loads of the system such as sensitive cooling and total cooling, ending with the latent load (all this in KW).

a)
Thermal balance b) Cargas of the system c) Latent charge Figure 5. Internal thermal gains from architecture The thermal sensation is modified from person to person in the same area and instantly, so it is thought that even when the expected average vote value (PMV) is neutral, there is a percentage of dissatisfied people. Adding to the above Fanger's method [42], proposes relationship for the evaluation of thermal dissatisfaction called "estimated percentage of dissatisfied" (PPD ). The PPD indicates the percentage of people who will eventually feel excessive heat or excessive cold in a given environment [43]. PPD is a function of PMV Figure 6. the function of PPD Vs PMV crossed with the current design condition.

Discussion
The thermal balance has a load gain in KW inside the house, which represents an elevation of temperatures inside it. Consequently, to the above, this thermal gain is presented in large part by the heat transfer obtained between the outside and inside of the enveloping walls by means of transmittance and solar gains (see Figure  7).

Figure 7. Internal gains plus solar gains in studio architecture
Using PPD Vs PMV [44], [45], rendering to ASHRAE 55 [46], establishes that thermal comfort is achieved on the basis of a satisfaction rate of the inhabitants greater than 80%. The excess share of people can feel 10% body dissatisfaction. To comply with this standard, the recommended thermal frontier at the 7-point PMV level is between -0.5 and 0.5. PPD can fluctuate between 5% and 100%, but comfort ranges meets standards, no occupied spots in the area should be above 20% PPD [46]. Based on this, the housing disconfort is determined in this house, since the PPD is at intersection with the PPD vs PMV function at 36.35% and the PMV at -1.4 per thermal sensation of heat and 1.1 by the thermal sensation of cold (See Figure 8. ).

Conclusion
It is presented to a conventional townhouse of dry warm climate case study in the city of Bucaramanga, which, is built with common materials of the area thought only of mechanical and structural resistance since this area is a seismic nest of Latin America for its location close to several geological faults [47]- [48]- [49]- [50]. It is performed characterization of thermal constants such as thermal transmittance, thermal resistance and thermal compactness of the structural components of the case study. Subsequent testing takes into account the variables already identified to decrease the error rate in computational tool calculations.
The latent loads if presented is its maximum points when the inhabitants are inside the house, since when analyzing the architecture as a single-family home it is assumed that the people who inhabit it will be only in hours outside of working hours, so some variables oscillate depending on the solar moment and the occupation and activity of equipment.