An update of a simulation study of passively heated residemtial buildings

A simulation study of passively heated residential buildings” published in Procedia Engineering 2015 showed how circulating 15-17ºC water from a 50-m deep U-tube to a floor radiator and solar-heated water from a 30 evacuated tube solar collector and a 2-m3 indoor tank to a wall radiator could keep a 30-m2 Melbourne, Australia house thermally comfortable. This paper presents a summary of the ongoing review of publications together with three updates: - (1) Report on that water heated by a 100-metre deep U-tube is 22-24ºC, i.e., 2-4 ºC warmer than thermal comfort temperature. (2) May 2016 experimental validations of the simulated results which show that when the outdoors is below 10ºC, the temperature of the floor radiator is 2-4ºC less than the 15-17ºC water heated by a 50-m deep U-tube and 25 W fish tank pumps could circulate the waters. (3) Simulations with the addition of phase change materials (PCM) to inside faces show that though a PCM halves the diurnal indoor temperature variations, it confirms that such PCM does not significantly increase the 20ºC temperature in a 2-m3 storage tank at the end of winter. Therefore, the size of intersessional thermal storage would be a problem for family-sized houses. German Guidelines indicate that 1-2 boreholes could provide enough heat for family-sized houses. The heat extracted in winter can be replenished in summer. Thus the geothermal heat from about 100-m deep boreholes with 22-24ºC bottom temperature could sustainably keep residential buildings in cool climates similar to Melbourne's cool temperate thermally comfortable

A Simulation Study of Passively Heated Residential Buildings

This research aims to gain understanding of the key design aspects in using renewable sources (e.g., geothermal and solar) for residential heating. To achieve this aim, a simulation study has been undertaken by using the EnergyPlus™ software Version 8.1. First a brief review of the literature was carried out, which covers solar ground-source heat pump, solar-heated water, lowtemperature wall and floor surface radiators, types of solar collector, fixed tilt versus solar tracker, and cost versus savings. Then the conceptual design idea and energy simulation process are described. Following this a simulation study of a 30 m2 onebedroom simple house, as a case example was carried out. The results show that, with two surface radiators, a 30 m2 house would remain within the acceptable thermal comfort temperature range in winter. The simulation results also show that the floor radiator, fed with water from U-tube in deep ground warms the concrete-in-ground floor, which would otherwise be cold for more than half a year. The simulation results also show that the wall radiators, fed with water (stored in a 2 m3 indoor tank) heated by evacuated tubes make the indoors comfortable throughout the year. Furthermore, the results of additional 3-dimensional simulation show that, the creation of a thermal mass under the floor, using vertical insulation into the ground along its perimeter, may obviate the need of the floor radiator and borehole. In conclusion, the results of the simulation study show that it is feasible to utilise a combination of the renewable geothermal and solar energy to achieve indoor thermal comfort in houses. Future research is needed which includes validation of these simulations results with actual data collected from the case example and simulation study of more complex and larger scales residential houses

A Passive Malaysian Residential Building With A Hydronic Radiator

This paper presents a study to find a ‘green’ alternative to the conventional air conditioner seen on the walls of many residential buildings in Malaysia. EnergyPlus®, the official building simulation software of the US Department of Energy, is used to model a row of four units of modern low cost terrace housing, end walls facing East and West to minimize exposure to the sun’s ray. The high altitude of the tropical sun heats the metallic roofs to above 60°C during the day and the attic is naturally cooled by outdoor air infiltration through effective leakage area of 2342m2 per unit. Insulation of R-value 2.5 (m2.K)/W is added above the ceilings. Simulations are run with outdoor dry bulb temperatures that are exceeded, on average, by 0.4% (35 hours) in a year, for Kuching, in East Malaysia. Typical meteorological year data shows that the maximum nightly temperatures in Kuching are about 25°C and in West Malaysian cities with World Meteorological Organisation stations are about 26°C. When radiative heat loss to the dark night sky is included, water can be cooled to 25°C. Preliminary simulations verify that beam solar radiation enters through the windows, and external window shades lower the maximum indoor temperature in the hottest West end unit, unoccupied, by 0.6°C to 30.5°C. Night cooled water circulated to a hydronic radiator, then lowers the maximum ‘well-mixed’ operative temperature of the unit, occupied, to below 30.2°C. The indoor air is stratified to a hotter upper and a lower cooler layer, and the occupant’s environment is comfortable with air speeds of 0.8m/s

Size-selective purification of hepatitis B virus-like particle in flow-through chromatography: types of ion exchange adsorbent and grafted polymer architecture

Hepatitis B virus-like particles expressed in Escherichia coli were purified using anion exchange adsorbents grafted with polymer poly(oligo(ethylene glycol) methacrylate) in flow-through chromatography mode. The virus-like particles were selectively excluded, while the relatively smaller sized host cell proteins were absorbed. The exclusion of virus-like particles was governed by the accessibility of binding sites (the size of adsorbents and the charge of grafted dextran chains) as well as the architecture (branch-chain length) of the grafted polymer. The branch-chain length of grafted polymer was altered by changing the type of monomers used. The larger adsorbent (90 μm) had an approximately twofold increase in the flow-through recovery, as compared to the smaller adsorbent (30 μm). Generally, polymer-grafted adsorbents improved the exclusion of the virus-like particles. Overall, the middle branch-chain length polymer grafted on larger adsorbent showed optimal performance at 92% flow-through recovery with a purification factor of 1.53. A comparative study between the adsorbent with dextran grafts and the polymer-grafted adsorbent showed that a better exclusion of virus-like particles was achieved with the absorbent grafted with inert polymer. The grafted polymer was also shown to reduce strong interaction between binding sites and virus-like particles, which preserved the particles' structure

Remote control of robot with active feedback

Telerobotics, or the remote control of robots has been around for some time. Most cases use a master device that remotely controls a slave tele-manipulator. Research in the remote control of robots with active feedback, that is, telemanipulation with simultaneous feedback of two or more variables from the slave to the master is ongoing. This thesis considers the feedback of two variables, position and torque, of the slave motor to the remote master in a model that includes a human operator that interfaces with the force-feedback joystick of the master motor of the master-slave combination.Master of Science (Computer Control and Automation

A step towards the Washington Accord (1989)?

The Washington Accord was first signed in 1989 by US, UK, Australia, New Zealand, Ireland and Canada. It applies to the accreditation of engineering education programs. Hong Kong signed in 1995, South Africa in 1995 and Japan in 2005. This paper is an account of the corresponding author's experience in the developments of the engineering education in Singapore (in the 1990's) and Malaysia (in the 2000's) who are provisional members to the Washington accord. It hopes to support the admission of Malaysia as a full member

Verification of the Performance of a Vertical Ground Heat Exchanger Applied to a Test House in Melbourne, Australia

The ground heat exchanger is traditionally used as a heat source or sink for the heat pump that raises the temperature of water to about 50 °C to heat houses. However, in winter, the heating thermostat (temperature at which heating begins) in the Australian Nationwide House Energy Rating Scheme (NatHERS) is only 20 °C during daytime and 15 °C at night. In South-East Melbourne, the temperature at the bottom of a 50-meter-deep borehole has been recorded with an Emerson™ recorder at 17 °C. Melbourne has an annual average temperature of 15 °C, so the ground temperature increases by 2 °C per 50-m depth. A linear projection gives 23 °C at 200-m of depth, and as the average undisturbed temperature of the ground for a 400-m-deep vertical ground heat exchanger (VGHE). This study, by simulation and experimentation, aims to verify that the circulation of water in the VGHE’s U-tube to low-temperature radiators (LTRs) could heat a house to thermal comfort. A literature review is included in the introduction. A simulation, using a model of a 60-m2 experimental house, shows that the daytime circulation of water in this VGHE/LTR-on-opposite-walls system during the 8-month cold half of the year, heats the indoors to NatHERS settings. Simulation for the cold half shows that this VGHE-LTR system could cool the indoors. Instead, a fan creating a cooling sensation of up to 4 °C is used so that the VGHE is available for the regeneration of heat extracted from the ground during the cold portion. Simulations for this hot portion show that a 3.4-m2 flat plate solar collector can collect more than twice the heat extracted from the ground in the cold portion. Thus, it can thus replenish the ground heat extracted for houses double the size of this 60-m2 experimental house. Therefore, ground heat is sustainable for family-size homes. Since no heat pump is used, the cost of VGHE-LTR systems could be comparable to systems using the ground source heat pump. Water circulation pumps and fans require low power that can be supplied by photovoltaic thermal (PVT). The EnergyPlus™ v8.7 object modeling the PVT requires user-defined efficiencies, so a PVT will be tested in the experimental house

A Comparison between Genetic Algorithms and Evolutionary Programming based on Cutting Stock Problem

Programming (EP) are two well-known optimization methods that belong to the class of Evolutionary Algorithms (EA). Both methods have generally been recognized to have successfully solved many problems in recent years, especially with respect to engineering and industrial problems. Even though they are two different types of EA, the two methods share a lot of commonalities in the genetic operators they use and the way they mimic natural evolution. This paper aims to bring forth an introductory review on how these two methods tackle the one-dimensional Cutting Stock Problem (CSP). We draw comparison on the effectiveness of GA and EP in solving CSP, and propose an improved algorithm using a combination of the two methods based on our observations. In the concluding remarks, some future works are suggested for further investigations. Index Terms—Cutting stock problem, evolutionary programming, genetic algorithms, optimization methods. I

An Update of a Simulation Study of Passively Heated Residential Buildings

“A simulation study of passively heated residential buildings” published in Procedia Engineering 2015 showed how circulating 15-17°C water from a 50-m deep U-tube to a floor radiator and solar-heated water from a 30 evacuated tube solar collector and a 2-m3 indoor tank to a wall radiator could keep a 30-m2 Melbourne, Australia house thermally comfortable. This paper presents a summary of the ongoing review of publications together with three updates: - (1) Report on that water heated by a 100-metre deep U-tube is 22-24°C, i.e., 2-4 °C warmer than thermal comfort temperature. (2) May 2016 experimental validations of the simulated results which show that when the outdoors is below 10°C, the temperature of the floor radiator is 2-4°C less than the 15-17°C water heated by a 50-m deep U-tube and 25 W fish tank pumps could circulate the waters. (3) Simulations with the addition of phase change materials (PCM) to inside faces show that though a PCM halves the diurnal indoor temperature variations, it confirms that such PCM does not significantly increase the 20°C temperature in a 2-m3 storage tank at the end of winter. Therefore, the size of intersessional thermal storage would be a problem for family-sized houses. German Guidelines indicate that 1-2 boreholes could provide enough heat for family-sized houses. The heat extracted in winter can be replenished in summer. Thus the geothermal heat from about 100-m deep boreholes with 22-24°C bottom temperature could sustainably keep residential buildings in cool climates similar to Melbourne's cool temperate thermally comfortable