Month: October 2016

It is no secret that cities use up a large bulk of the energy budget. Thus sourcing for more renewable and reliable sources of energy is always important.

Ocean Thermal Energy Conversion (abbreviated OTEC), interestingly generates energy through the temperature difference between surface and deep sea waters (1).

(2)

The idea is very similar to coal-fired power plants, where heat is used to excite a fluid, in this case it is ammonia (1), and the excited fluid moves and turns a turbine that produces energy. I have a few personal thoughts on this, and by any means I may be wrong.

It is definitely a very interesting idea. Although it is stated that hot & cold waters are respectively drawn out from the shallow and deep waters, and consequently the mixed, thermally averaged water is released back, the energy used to turn the turbines have to come from somewhere. Therefore the ocean ‘system’ actually loses energy as a whole. As there is a net loss of energy from the ocean to turn the turbines, I wonder whether, on a large scale, it is viable to possibly also conveniently mitigate the onset of rising sea temperatures & its subsequent ramifications on wildlife and habitat?

However I also question its effectiveness to produce energy. Comparing it to current coal plants, where coals is fired to produce steam, the temperature of coal can go up to almost 2000°C (3). The maximum difference in temperature between the coldest and warmest waters would be merely ~20°C. How effective will this technology be in displacing conventional fossil fuels?

In a city like Singapore, if this technology would be proven effective, I would think that this would be pretty viable for us, as we are situated right smack in the tropics, possibly having one of the highest surface sea temperatures.

So many ideas, yet so unattainable.

References

1. What is OTEC –. OTEC news. Retrieved 28 October 2016, from http://www.otecnews.org/what-is-otec/
2. Ocean Thermal Energy Conversion | Makai Ocean Engineering. Makai.com. Retrieved 28 October 2016, from http://www.makai.com/ocean-thermal-energy-conversion/
3. Coal and Charcoal. Anvilfire.com. Retrieved 30 October 2016, from http://www.anvilfire.com/FAQs/coal.php

Remember my previous post “Water Body”? Well, this is the sequel. Water Body v1.2

Seawater Body.

(creative commons)

Water Body was all about how there are various ways to cool a city down, and I introduced a concept, Deep Water Source Cooling (abbreviated DWSC), that makes use of ponds/ reservoirs i.e. bodies of water to replace air-conditioning. I discussed a little of its limitations, but recently I read about this: Sea-water air-conditioning.

Similar to the concept of DWSC, water is drawn from the lower depths, pass it through a heat exchange unit and the warmed water is discharged and returned. MAKAI, the company marketing this system, claims that it can save 90% of the energy used in air-conditioners that rely on air compressors (1). Perfect. Furthermore we do not use up fossil fuels in this method of cooling, alleviating a host of problems like global warming and air pollution.

(1)

Remember how I criticized DWSC to be unfeasible in Singapore as we are summer all year round? Well, nature has a robust answer. Thanks to oceanic convection currents, i.e. difference in temperature between the equator and the poles that produce a huge global-scale convection, sea water will be more cool, for one, and also there’s no worry that constant discharging of warmer water will cause the temperature of the said water body to rise insidiously without decreasing, as will be the case for closed systems like ponds/ reservoirs.

Even though the deep seawater around the equator may not be as cool, MAKAI has estimated that the energy usage of this system will still be 1/4 of that of a conventional compressor air-conditioner (1). Interesting times ahead, considering Singapore is a city-island surrounded by water.

Viable? Maybe. Some places in Hong Kong for example are currently doing it. Will it happen? We never know. Considering our rampant land reclamation projects at hand, installing pipelines that restrict our ‘growth’ may not be exactly what the government has in mind.

^^cheers

References

1. Sea Water Air Conditioning | Makai Ocean Engineering. Makai.com. Retrieved 15 September 2016, from http://www.makai.com/sea-water-air-conditioning/

If life were stop motion, what would I be? Would I choose to live at 1 frame a second? Or 2? Would there be a difference?

If life were stop motion, would I still be able to play the games I love or talk to the people I want? Will the things I used to own feel the same to the touch? Would I be able to sense the sun caressing my face, if the frames always froze?

If life were stop motion, would a slight drizzle or heavy downpour, feel any different? Would the howling winds echo in my ears, could I savour the scent of rain?

If life were stop motion, would the fluttering wings of a butterfly be less stunning? Would a dolphin’s leap still seem so graceful?

If life were stop motion, would everything around me lose its lustre? Would I regret my choices?

If life were stop motion, will I live voraciously? Or will I be disheartened.

If life weren’t stop motion, I know, I would never, take these things for granted.

(creative commons)

A short poem about sustainability, inspired by stop motion videography.

Have you ever wondered, that people living in cities are so paradoxical? It’s hard to please us, because we, are so confusing. We want to feel cool, but when bathing, the water hot. One moment we consume iced drinks, the next minute, snuggle in our blankets, with the air-conditioning blasting while we sleep.

(creative commons)

This generates a lot of energy wastage, from my idealistic point of view, heat energy isn’t going to where it’s needed most i.e. inefficient distribution. Recently I read up about this idea of the Solar Pond. It is not state-of-the-art technology, in fact it has been around for a few decades already. Funny that it took me this long. Nevertheless…

Like many others, it is an ingenious idea, based on simple concepts. A normal column of water naturally has its convection currents ongoing, and after a substantial amount of time untouched, it would be in thermal equilibrium.

(2)

Basically, in this tub, the base designed to be super heat-absorbing, possibly coloured black, and copious amounts of salt is added to the water residing inside. As high salinity water sinks to the bottom due to the force of gravity on density,  it creates a steep salinity gradient, where the water below is saturated, while in an ideal situation the top layer is unsalted (2). As the entire pool is heated up together by the sun, convection currents do not surpass the salinity gradient, and thus heat from the bottom does not convect up and gets lost in the atmosphere (3). The figure below shows all the major processes that goes on in a typical solar pond.

(1)

The heat trapped below can be transferred and used in cities for use, and this way, harnessing the renewable energy of the sun, we cut down on fossil fuel usage and its harmful aftereffects.

An idea I can think of is possibly installing these in rooftops? Instead of wasting money on heaters and boilers, the solar pond may indeed be a solution. There seems to be however some maintenance complications, like the crystallizing of salts and eventual evaporation of the water (2), rendering this idea not too feasible, but I believe this development may only be in its infancy, and we thus have to rely on great, bright engineers, to solve these sticky issues for us.

Meanwhile, re-read paragraph 1 and REPENT!

References

1. González, D., Amigo, J., Lorente, S., Bejan, A., & Suárez, F. (2016, April 05). Constructal design of salt-gradient solar pond fields. International Journal of Energy Research Int. J. Energy Res., 40(10), 1428-1446. doi:10.1002/er.3539
2. Solar Ponds Will Determine the Future of Energy Creation. Solar Energy For Homes. Retrieved 20 September 2016, from http://www.solar-energy-for-homes.com/solar-ponds.html
3. Solar pond. Edugreen.teri.res.in. Retrieved 20 September 2016, from http://edugreen.teri.res.in/explore/renew/pond.htm