---

Dual skin facade is an architectural concept originally intended for office buildings and indeed considered and implemented extensively. The façade to the building actually is a skin, but consist of two layers (the internal and external) which could be out of different glass types, they are separated by in-between air-gap and it is capable of air ventilation. The external skin protects the building not only against the climate hazards, but also can reduce noise pollutions significantly. The residents could take advantage of adjustable windows regardless of the element types such as wind and gust, the adverse effect of direct sunlight (glare), the environmental pollutions, and so on. Shading mechanisms allow the inner rooms of the building to benefit from an indirect sunlight while reducing the load on HVAC in cooling down the building in summers. Dual skin facades function as a heat conserver in cold climates in a way that stores the radiated energy in the air-gap whose temperature is almost made equal to the one of the temperature inside the building. In addition to providing the needed light within, indeed the external glass of the dual skin systems is capable of absorbing the light and storing heat in the winter, also induces natural ventilations in the summer to reduce the same sun light related heat. This is how the dual skin system helps in reduction of the heating and air conditioning load also with the internal air quality. Tolerance of the temperature above 24 degree Celsius in the buildings without natural air condition such as closed HVAC is difficult. While in buildings with natural air conditions the temperatures of even above 27 degree Celsius is pleasant. This reduces the energy consumption in the building. Therefore in this paper while studying the methods of using this system in hot arid climates, for the purpose of taking advantage, analysis and optimization of natural ventilation of double skin facade as one of the most important factor in hot and dry climates are considered. The layers to dual skin façade include the External Skin, the Internal Skin, and the air-gap in between the two. The External Skin (Façade): Generally it is a singular toughened glass, and the external skin could be made completely out of it. The Internal Skin (Façade): They are thermal insulating double pane glasses and could be made completely out of glass. Varieties of solar glasses could be applied. The in-between the Two Glasses Air-gap: The air-gap could be ventilated completely natural or mechanical. The air-gap width varies anything from 20cm to 2 meters thick, and it could be effective when applied as a support. The windows are users accessed to allow ventilation; also the shading could be consolidated and controlled by an automated system within the air-gap. Plans for the Direction of Air Current There are three suggested air ventilation plans in construction of a façade: To ventilate inward (Type A): The air tends to drift away from within the building to the air-gap, and the fresh air to the facility is replaced from outside. The air in the A type flows outward from the rooms, enters the air-gap and continues to move passing above the rollers to the awnings. In some designs, the air is guided out or through the duct is returned to central heating or A/C systems of the building. Ventilation Combo (Type B & C): The air is guided outward through the air-gap or vice versa. In cold climates, the B & C types can have a pre heating effect on the air before it enters the rooms. The ventilation system of A, B, & C are mechanical and they could be implemented in conjunction with the HVAC system of the building. The air is ventilated out of the building (Type D): The fresh air from outside is guided inward through the air-gap and then it is ventilated outside. The D type as a breather to the dual skin façade is implemented along with natural ventilation mechanism. The system may allow the fresh air inward through open windows and when closed may function as a thermal insulator providing a suitable thermal stability. With reference to the conducted research and with consideration to the contributing parameters, the numerical analysis of natural ventilation in dual skin façades is as follows:In order to achieve the most optimum performance of the dual skin façades in hot and arid climate considering the suggested specifications, for natural ventilation in the said type of climate, a dual skin façade sample is designed. The numerical analysis of the sample design generated by GAMBIT and FLUENT with which the numerical analysis of the dual skin façade is conducted. The intended case study is an imaginary 3 story high building in which there is a single room allocated to each floor. The allocated air-gap size of the dual skin façade is 50cm. There is a window to each floor allocated to both the inner and the outer skin with variable dimensions of 0.6 ,0.4, and 1.0 meters. The current case study is analyzed in hot and dry climate of Kerman city located on 38 ’17 ○30” N. Latitude and 3 ’5 ○57” E. Longitude. As a result, the numerical output of this software show that the two-shelled buildings help to taking advantage of natural ventilation and improve indoor air quality and it will be more effective in order to reduce the use of air conditioning systems and to achieve a comfortable temperature. Dual skin façades are utilized in office building a lot and looking back at the conducted research and considering numerous applications of the said façades is ever more advantages for using the elements such as weather, and specifically implementation of natural ventilation in balancing the in-building temperature, also a significant reduction in the use HVAC in the buildings; therefore, here is the model of choice recommended the best for hot and arid climate in residential buildings too

---

---

---

Aims: The main purpose of this article is to introduce the model of healthy building in the interaction of choosing building materials and healthy environment. In this regard, high throughput screening used in construction materials for possible human exposure in the near field and related health risks, identification of chemicals and products of interest to inform risk reduction efforts has been carried out.
methods: The research methodology is based on the theoretical saturation of the research background and the opinions of experts in the field of health of residents at home and at work. Using high throughput screening, hazardous chemicals in the construction industry were identified, and based on the theoretical saturation of the research background and the opinions of experts in the health of residents at home and at work, a focused group discussion method was used.
Findings: Comparing the quality of "healthy building" with three variables of building chemistry, building biology and building physics; and "residents' opinion" with three variables of energy efficiency, residents' satisfaction and residents' health; has been analyzed. The findings of the focused group discussion method clarified various dimensions of the relationship between building chemistry and the health of residents at home and at work.
Conclusion: Designers and manufacturers of building products must actively track and manage the chemical composition of their materials and assess the potential impacts of the chemicals of interest throughout their life cycle. High-throughput screening can provide accessible and rapid tools for such evaluations at the design stage.
 

---

In this study, the effect of inlet supply temperature on energy consumption optimization, thermal comfort and mean local air age has been investigated for a displacement ventilation inside a typical room. Based on the results obtained from this study, an increase in the inlet supply temperature for a displacement ventilation from 17.8 to 25.8 in summer leads to a 50% reduction of consumed energy. Owing to the fact that optimization of consumed energy is an action bound to maintain thermal comfort of occupants, PMV(predicted mean vote) and PPD(predicted percentage of dissatisfied) parameters as two general thermal comfort indices have been investigated. In addition temperature gradient in vertical direction as local thermal discomfort index and mean local air age as air quality index have been probed. All the aforementioned indices except that of mean local air age, lie within the sightly range of ISO7730 standard with an increase in temperature, but air quality index experiences some quality drop in inhalation region, This slight drop is negligible and displacement ventilation system can be used as a suitable ventilation system for summer applications.

---

In this study, by cooling coil load calculation in under floor air distribution systems, the effect of separate location of the return and exhaust vents and return vent height on energy consumption, thermal comfort conditions and indoor air quality have been investigated. Based on the results obtained from this study, when the height of return vent is equal to 2.0, 1.3, 0.65 and 0.3 m, the amount of energy usage reduction compared to no return vent is equal to 10.9, 15.3, 18.9 and 25.7 percent respectively. Limiting factors in the amount of this reduction are thermal comfort of occupants and indoor air quality. To this end, thermal comfort indices (Predicted Mean Vote and Predicted Percentage of Dissatisfied), local thermal discomfort index (Temperature gradient in vertical direction), and indoor air quality index (Mean Local Air Age) have been probed with changing return vent height by CFD methods (AirPak software with SIMPLE algorithm by using Indoor Zero Equation turbulence model). Based on the results, by reducing the height of return vent from ceiling to floor, the exhaust air temperature increased, which causes to temperature gradient increase in vertical direction. The survey was conducted that choosing the location of 1.3 m(upper boundary of occupied space in seated mode) for return vent, causes to 15.3 percent reduction in the amount of energy consumption while maintaining the states of thermal comfort conditions and indoor air quality.

---

In this study, the effects of discharge angle from an air curtain’s jet have been investigated on aerodynamic sealing of a room with positive pressure ventilation system. For this reason, the modeling of flow, heat transfer and species diffusion has been performed by using OpenFoam® numerical solver. The results show that the jet discharge angle has significant effects on the distribution of parameters such as temperature, concentration of pollutants and occupants’ thermal sensation index. So, by varying the jet discharge angle from +10 (towards the indoor space) to -10 (towards the outdoor space), the average temperature difference between two spaces is reduced to 2.5°C. Also, the mentioned varying in discharge angle causes a significant reduction in the mean concentration of pollutants at the indoor space, from 25ppm to 5ppm. On the other hand, the results indicated that for the discharge angle of -10, the average of occupant’s thermal sensation index is shifting to the cool feeling. Therefore, the mentioned discharge angle can reduce the impacts of outdoor warm conditions on the indoor’s. In other words, the discharge angle of -10 demonstrates the best performance of the air curtain device in thermal and aerodynamic separating of two indoor and outdoor spaces.

---

Due to high humidity, high air temperature and hazardous compounds including chlorine indoor swimming pools are called as ‎unhealthy environment. Therefore, the pollutants’ concentration, relative humidity and thermal comfort conditions must be ‎simultaneously considered in designing the air conditioning systems of indoor swimming pools. In this study, a new approach has been ‎presented for concurrent modeling of water evaporation mechanism, chlorine concentration level, occupants’ thermal sensation and ‎temperature and velocity fields in a championship-size indoor swimming pool. In this regard, a new algorithm has been developed in ‎order to apply adaptive boundary conditions at water-air interface in the pool. In the mentioned pool, the air enters the environment ‎through a linear ceiling diffuser at temperature of 35°C, relative humidity of 30% and air exchange rate of 4 times per hour. The results ‎show that the distribution of temperature, relative humidity and concentration of chlorine contaminant are significantly depending on the ‎height from the water surface. So, the volumetric average of relative humidity from the floor to 0.5m height is about 62%; while the ‎volumetric average of relative humidity in the occupied zone is about 50%. Moreover, results indicate that in the distance of floor to 0.5m ‎height, the mean value of chlorine’s concentration is about 60% larger than its mean value in the occupied zone. Also, the temperature ‎field and distribution of thermal comfort index are significantly dependent to the height.‎

---

Nowadays, modern windows with standard caulking used in most buildings. Study of air infiltration and caulking this windows in several ways such as energy, indoor air quality, thermal comfort and pollution entering in the building is important. In this study consists of two parts, first experimentally investigated the airtight performance of various window gaskets. For this purpose, using 8 different types of gaskets and simulate modern window gap, air infiltration rates measured at different pressure differences. The results show that the airtight performance of various gaskets are different. Also fitted the experimental results by power low equation, and relations and coefficients for calculate air infiltration rate of modern windows (sealed windows), respectively. In the second section due to the very low air infiltration rate of the experimental results, indoor air quality assessed by numerical modeling methods. In the sample model, air infiltration of modern windows as ventilation and human breathing as a source of CO2 simulated. Indoor air quality is weighed by the CO2 concentration in the interior space. The results show that the air infiltration of window gaps to ensure air quality during the 8 hours is not enough. Then, assuming uniform distribution of CO2 in the sample space, and solve the transfer species equation for the problem situation, analytical equation for evaluating indoor air quality were achieved. Analytical results matches on numerical simulation results exactly. The results of this study can be very useful for HVAC engineers.

---

Estimating indoor air pollutants to ensure the air quality is very important. In this study, a conventional residential space is numerically simulated in order to investigate the behavior of pollutants. Using the numerical results and the experimental results of other references, proposed the analytical relation to estimate the concentration of CO2 in term of factors such as CO2 produced by breathing residents or combustion equipment, the volume of space and ventilation rate. The results of the analytical relation are full compliance with experimental and numerical results and it can be used to estimate indoor air quality. Proposed relation can be used in all the same cases.

---

Nowadays, the building ventilation is an essential process, due to need of improving the air quality and thermal comfort conditions for occupants. Providing the mentioned conditions is more complex for crowded and larger spaces. In this study, the effects of air change rate per hour (ACH) on thermal comfort, indoor air quality and energy consumption in an amphitheater with under floor air distribution system have been investigated by using the computational fluid dynamics and Open Foam numerical solver. For this issue, an amphitheater with 50 occupants has been modeled under the conditions that the air inlet diffusers located in front of seats. Also, the air change rate per hour is assumed to be 5, 10 and 15. For better comparison between the results, inlet air temperature is controlled until the mean of thermal comfort index (TSENS) in the occupied zone equals to zero. The results indicate that for air change rates of 15, 10 in comparison with ACH of 5, the CO2 concentrations in the occupied zone are respectively reduced about 36 and 46 percent and so the indoor air quality is improved. On the other hand, the energy consumption is increased about 28 and 69 percent, respectively. Also, based on the results, by increasing the ACH rate, the draft local discomfort is significantly increased and can be reached at the amount of 15%.

---