Improving Energy Efficiency by Utilizing Wetted Cellulose Pads in Passive Cooling Systems

The effectiveness of using wetted cellulose pads on improving the performance of two conventional passive cooling systems has been evaluated. First, an experimental design was developed to determine the impact of using a wetted cellulose pad on the temperature and velocity of the airflow. A cellulose pad (7090 model) with a cross-sectional area of 0.5 × 0.5 m2 and three different thicknesses of 10, 15, and 30 cm were selected and tested. The results indicated that using wetted cellulose pads with thicknesses ranging from 10–30 cm decreased the outlet airflow temperature from 11.3 to 13.7 °C on average. For free airflow at velocity 3.5 m/s, the outlet airflow velocity from the wetted cellulose pad decreased to 0.9, 0.7 and 0.6 m/s, respectively, for cellulose pads with thicknesses of 10, 15, and 30 cm. By applying experimental results on a psychrometric chart, the humidity ratio of outlet airflow was obtained between 40–70%. The study established airflow velocity as the critical parameter in passive cooling systems. With the novel concept of combining wetted cellulose pads for passive cooling systems (i.e., wind catchers and induced ventilation), there is good potential to reduce the energy requirements for thermal comfort in buildings in regions with a hot and arid climate.

Adaptation of a container tank to a savonius vertical axis turbine analyzed by reverse engineering

Due to the alarming climatic situation experienced by all nations, we are in the need to urgently develop and improve sustainable technologies for power generation in order to supply the growing demand for power generation in power systems worldwide. This project aims to design and build a prototype vertical axis wind turbine Savonius analyzed by reverse engineering process by adapting the structure of a tank and taking advantage of its shape and dimensions, with the intention of building a wind turbine with the lowest possible budget, In addition, data from the psychrometric chart of the state of Puebla (winter-spring) will be used so that by means of numerical simulations of fluid flow using CFD software we can obtain the parameters of linear velocity, angular velocity, drag coefficient and projected power that the wind rotor will be able to develop.

The Relation between Effective Temperature and Thermal Sensation Vote in Tropical Vernacular Houses

One of the factors to enable energy efficiency in buildings is creating thermal comfort for the occupants of buildings so that the artificial vaporization is not required. The thermal sensation vote (TSV) is an indicator in analyzing the occupants’ satisfaction on the thermal comfort of their buildings. Some climate variables that relate to the TSV include air temperature, humidity, and wind speed. The three variables can be combined into a variable using a psychrometric chart. The combined variable is known as an effective temperature. The present research aims at analyzing the connection between effective temperature and TSV in vernacular houses in the tropical mountain and beach locations and comparing the results of the analysis. The quantitative method was employed in the research by measuring the variables of climate using a thermal measuring instrument. The TSV was measured with ASHRAE (American Standard of Heating, Refrigerating, Air-Conditioning Engineer)’s seven-point sensation scale. The measurement was carried out in transitional periods from the dry season to the wet season. Interpretation of graphs and charts was made for analysis based on the variable of effective temperature. The results of the research indicated that there was a connection between effective temperature and TSV. The effective temperature in vernacular houses in tropical mountain locations tended to be lower, and therefore the cool thermal sensation had the greatest percentage of TSV. Meanwhile, the effective temperature in tropical beach locations tended to be high, and therefore the warm thermal sensation had the greatest percentage. In a neutral scale, the percentage of TSV in tropical mountain locations was greater than that of TSV in tropical beach locations. Therefore, it is concluded that the occupants of vernacular houses in tropical mountain location felt more comfortable than those of vernacular houses in tropical beach locations.

STUDI COOLING CAPACITY KAPAL CEPAT RUDAL 60 METER (STUDI KASUS PADA KCR 60 BATCH DI PT PAL INDONESIA)

Perkembangan dunia perkapalan maupun dunia maritim harus diimbangi dengan peningkatan mutu alat transportasi, terutama untuk alat transportasi laut. Pada alat transportasi tersebut beban pendinginan pada tiap ruangan perlu dilakukan perhitungan secara teliti untuk mendapatkan nilai efisiensi yang baik. Tujuan dari studi ini adalah untuk menganalisis dan mengetahui parameter-parameter yang mempengaruhi nilai dari kapasitas pendinginan pada Kapal Cepat Rudal 60 Meter, seperti parameter volume ruang, parameter kondisi udara luar dan udara dalam ruang, parameter beban panas yang diderita pada ruangan, parameter Fresh Air, parameter psychrometric diagram, serta kapasitas pendinginan yang dibutuhkan. Metode yang digunakan adalah menghitung nilai h yang didapatkan dari psychrometric chart. Langkah selanjutnya adalah menentukan nilai RSHF. Langkah ketiga adalah menentukan cooling capacity tiap ruangan. Hasil yang didapatkan adalah nilai dari total kapasitas pendingin (Cooling Capacity) yang dibutuhkan oleh kompresor pada ruang akomodasi Kapal Cepat Rudal 60 Meter sebesar 174,17 kW. Hasil tersebut dari perincian data berupa kapal dirancang dalam Summer Condition (iklim tropis) dengan temperatur inside = 22˚C dan temperature outside = 35˚C, Jumlah Beban Panas Transmisi = 20651Watt, Jumlah Beban Panas Jendela = 1192 Watt, Jumlah Beban Panas Lampu = 56817 Watt, Jumlah Beban Panas Penghuni (Sensible + Latent) = 104494 Watt, Jumlah Beban Panas Peralatan = 12400 Watt, Jumlah Beban Panas Total = 103737 Watt.