Monthly Archives: February 2015

Options for hot water

Energy consumed in heating water may not appear like a major problem, compared to industries, but thousands of homes each with 2 or 3 heaters may surpass many industries in energy consumption.

28PP-greensense_28_2325243eIt is easy to get an instant answer to the question “what’s the single major reason for high electricity bills in homes.” It is electric geysers. Yes we know, yet we have no single solution acceptable to all to get our daily supply of hot water. The last decade has produced a few viable alternatives, but they have not yet replaced the age-old geyser.

The challenge of hot water lies in the very nature of its need and this challenge can only be met with by using cold water! Unfortunately such a suggestion would get laughed at as impractical, for hot water bath has been part of our civilisation, biologically or culturally.

Though we need hot water mostly during the morning hours, it could also be needed at any time depending on the family lifestyle and guest arrival, with varying water quantity each time. Therefore, electric geyser comes to stay as an anytime, any quantity solution. On a quick look, energy consumed in heating the water may not appear like a major problem at all, compared to say some industry; but thousands of homes each with 2 or 3 heaters may surpass many industries in energy consumption. The problem is getting critical even in rural areas, with firewood getting depleted at rapid rate.

Solar water heaters have emerged as an effective alternative to the electric geyser, with 300 sunny days in a year in most areas of India. Roof-top installations, panel facing south, could be seen everywhere today, both on flat roofs and of late, sloping roofs too. The water storage tank comes with a built-in electricity geyser, an option which is not very desirable. In case of water not being hot enough, we end up heating all of 100 or 200 litres of cold water, consuming much more energy.

If really hot water is expected, we can route the solar water through a conventional electric geyser, thus reducing the power needed to heat up already warmed-up water.

Keep it simple

There have been complaints about lower water pressure if water is so routed, which can be resolved by the plumber. However, bringing solar water directly to the bathroom saves on extra connections, besides the confusing method of providing both fresh and solar water inlets for the geyser. One back-up electric geyser can be provided in the upper floor, with gravity flow to the ground floor baths.

Providing long piping for solar hot water is not advisable, considering the amount of cold water that flows first, before we get warm water. For this reason, avoid it in kitchens and wash basins. A larger family can save by staggering the bath timings, instead of installing higher capacity units. Also, locating it to get best sunlight hours is very important and so is occasional cleaning of the panel surface.

Most plumbers today know how to get the best from solar water heater connections, so it is time to look for other lesser known options.

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Is high-rise a solution?

Are high-rise residential blocks really eco-friendly as they claim? How do they fare in comparison to low-rise houses?

21bg_bgrag_gree_21_2317697eFrom full-page newspaper advertisements to huge hoardings along city roads, grand visions of high-rise apartments are popping out, enticing us to buy one today itself. Additionally, the catchy slogans like 75% garden, only 25% built and such others make us think as if we are going to live amidst green, though in reality we could be living in a crowded high-rise concrete tower with no green right outside our house.

The assured green could be in one large parcel at one part of the master plan, with no benefit to every living room of an apartment in the complex. Are these high-rise residential blocks really eco-friendly as they may claim? How do low-rise houses compare with high-rise single blocks?

Many such complexes have got green building certifications, but they are not based on embodied energy or options for low energy designs; instead they are based on the criteria laid out by the certifying agency.

Major difference

For the developer, utilising the maximum permitted built area called floor area ratio (FAR) is important for return of investment, so he would utilise the FAR equally, high-rise or low-rise. The major difference would be in the ground coverage, where the option of tall tower block would leave more ground area unbuilt, claiming it to be garden – a unique selling point.

Yardstick

In the architects’ professional circles, comparison between low-rise high density development and high-rise high density development has been an age old debate, with both the theories attracting their supporters.

However, if energy consumption and sustainability becomes the yardstick, high-rise apartments tend to raise more questions. They demand on site management, mass concreting, precise execution and an efficient supply chain to ensure smoother project completion. To that end, hi-tech practices, multiple high speed elevators and such others are a must both during and after construction with uninterrupted power.

Due to the extra efforts required in lifting materials and moving people to higher levels, labour costs increase with building height.

Maintaining the wall surfaces of tall buildings is a challenge, so the designers tend to opt for materials such as aluminium and glass, known for high cost and high embodied energy, besides many other manufactured materials.

If the walls are largely plastered and painted surfaces, their periodic repainting can be a humongous task, at great cost. Higher we go lesser we get to see the ground-level gardens and lesser accessibility to them, actually an anti-thesis to the selling point, whereas in low-rise apartments, there could be a visible open area outside each unit.

In a multi-level apartment, construction is sequential with each slab casting, but in a cluster of low-rise houses, it can be parallel, saving project time.

Many occupants of tall residential concrete towers complain about them being large and intimidating, while smaller group of houses can form social spaces and human scale – possibly a reason stronger than that of eco, to critically relook at high-rise houses.