Tag Archives: Indoor climate control

Air conditioning rise raises temperature

FOR IMMEDIATE RELEASE Studies into how we use air conditioning technology suggest that our attempts to keep cool are in fact adding to rising temperatures. LONDON, 27 August – As the world swelters, so will energy demand rise: the heat extremes generated by climate change are likely to raise the global demand for air conditioning by 72%. So people will generate more heat and release more carbon dioxide just to stay cool as the thermometer soars. Michael Sivak of the University of Michigan began asking questions earlier this year about whether air conditioning created more energy demand than central heating: he now reports in American Scientist that investment in air conditioning technology in the developing world could lead to an “unprecedented increase” in energy demand. Right now, the US uses more energy to keep cool than all the other countries in the world combined. “But this distinction might not remain true for long,” he says. “Several developing countries rank both among the most populous and hottest areas of the world. As personal incomes rise in those countries, their use of air conditioning will likely go up.” In just one Indian city, metropolitan Mumbai, he calculates there could be a potential demand for cooling that is about a quarter of the current demand of the entire US. In all, 87% of US households now have air conditioning and it takes 185 billion kilowatt hours of energy annually to keep American homes cool. But other countries have begun to turn down the thermostat. In 2010 alone, 50 million air conditioning units were sold in China. Air conditioning sales in India are growing at 20% a year. Cooling is a complicated business. Humans have only to step into their own homes to raise indoor temperatures: body heat – along with the heat from cooking, refrigeration and other activities – stays within the four walls. If the outdoor temperature is 18°C or more, then the surest way to keep the indoor temperature to an equable 21°C is to install air conditioning.

Demand to rise

Dr Sivak used an index of the potential demand for cooling – a quantity called annual person cooling degree days – to calculate future demand and work out what energy usage would be if air conditioning became as prevalent in other countries as it is in the US. Out of his top 25 countries, 14 were in Asia, seven in Africa and two each were in North and South America. The US has the coolest climate of these 25 countries, even though it has the highest demand for cool indoor breezes. Altogether, he reasoned, eight of the world’s nations have the potential to exceed US air conditioning use: India would surpass the US 14-fold if Indians adopted US standards of cooling; China more than five times and the Indonesians three times. Because 22 of the 25 countries are by World Bank definition low-income nations, demand is currently nowhere near its potential peak. But, he writes, future demand has the potential to exceed demand in the US by a factor of 50. The calculations are crude. They don’t factor in local variations in cloud cover, building design, available personal space, variations in energy efficiency or local difference in the tolerance of high temperatures. But, Sivak warns, as affluence increases, and as global average temperatures rise, so will demand: “This trend will put additional strains not only on global energy resources but also on the environmental prospects of a warming planet.” – Climate News Network

FOR IMMEDIATE RELEASE Studies into how we use air conditioning technology suggest that our attempts to keep cool are in fact adding to rising temperatures. LONDON, 27 August – As the world swelters, so will energy demand rise: the heat extremes generated by climate change are likely to raise the global demand for air conditioning by 72%. So people will generate more heat and release more carbon dioxide just to stay cool as the thermometer soars. Michael Sivak of the University of Michigan began asking questions earlier this year about whether air conditioning created more energy demand than central heating: he now reports in American Scientist that investment in air conditioning technology in the developing world could lead to an “unprecedented increase” in energy demand. Right now, the US uses more energy to keep cool than all the other countries in the world combined. “But this distinction might not remain true for long,” he says. “Several developing countries rank both among the most populous and hottest areas of the world. As personal incomes rise in those countries, their use of air conditioning will likely go up.” In just one Indian city, metropolitan Mumbai, he calculates there could be a potential demand for cooling that is about a quarter of the current demand of the entire US. In all, 87% of US households now have air conditioning and it takes 185 billion kilowatt hours of energy annually to keep American homes cool. But other countries have begun to turn down the thermostat. In 2010 alone, 50 million air conditioning units were sold in China. Air conditioning sales in India are growing at 20% a year. Cooling is a complicated business. Humans have only to step into their own homes to raise indoor temperatures: body heat – along with the heat from cooking, refrigeration and other activities – stays within the four walls. If the outdoor temperature is 18°C or more, then the surest way to keep the indoor temperature to an equable 21°C is to install air conditioning.

Demand to rise

Dr Sivak used an index of the potential demand for cooling – a quantity called annual person cooling degree days – to calculate future demand and work out what energy usage would be if air conditioning became as prevalent in other countries as it is in the US. Out of his top 25 countries, 14 were in Asia, seven in Africa and two each were in North and South America. The US has the coolest climate of these 25 countries, even though it has the highest demand for cool indoor breezes. Altogether, he reasoned, eight of the world’s nations have the potential to exceed US air conditioning use: India would surpass the US 14-fold if Indians adopted US standards of cooling; China more than five times and the Indonesians three times. Because 22 of the 25 countries are by World Bank definition low-income nations, demand is currently nowhere near its potential peak. But, he writes, future demand has the potential to exceed demand in the US by a factor of 50. The calculations are crude. They don’t factor in local variations in cloud cover, building design, available personal space, variations in energy efficiency or local difference in the tolerance of high temperatures. But, Sivak warns, as affluence increases, and as global average temperatures rise, so will demand: “This trend will put additional strains not only on global energy resources but also on the environmental prospects of a warming planet.” – Climate News Network

Cut your carbon: Stay warm, lose the lawn

FOR IMMEDIATE RELEASE Researchers may have found the way to a more comfortable life for suburbanites: garden lawns are more prolific carbon emitters than some farm crops, and keeping yourself warm uses much more energy than running an air conditioner. LONDON, 27 April – Here is some very limited advice on how to reduce your carbon footprint in suburban America: if you have a lawn, dig it up and plant a crop of maize. And if you live in Minneapolis, sell up and move to Miami. Two research papers in two journals have looked at two of those either/or questions that keep academics busy and dinner parties animated. Researchers at Elizabethtown College in Lancaster County, Pennsylvania, decided to look at what happens when farmland is converted to urban property. So for 10 weeks in the autumn of 2011, they visited and sampled the carbon dioxide release, soil moisture and temperatures, from urban lawns and from fields of corn, known also as Zea mays. They report in the Soil Science Society of America Journal that freshly mown grass sward won the dubious trophy for high greenhouse achievement. That is because lawns, on average, were hotter. “As you increase temperature, you increase biological activity – be it microbial, plant, fungal or animal”, said David Bowne, a biologist at the college. More biological activity meant more respiration, and more carbon dioxide releases. The higher lawn temperatures seem to be part of the urban heat island effect. Cities, notoriously, are much warmer than the surrounding countryside: roofs, roads, pavements and parking lots are dark, and absorb more sunlight, raising the ambient atmospheric temperatures overall. What the researchers had not quite expected, however, was to observe the effect on such a local scale. The research team found that urban development just 175 metres from a test location can cause an increase in temperature. The research is a small part of a much larger, global effort to understand what changes in land use do to climate.

Warmth is costly

  “If we go from one land use to another land use, how does that impact carbon cycling which in turn can affect climate change? Our study touches on one component of that cycle, and more research is needed to address this huge topic”, said Dr Bowne. Meanwhile, over at the University of Michigan, Ann Arbor, Michael Sivak asked himself the question: which demands more energy, air conditioning or central heating? He reports in Environmental Research Letters that he compared the costs of climate control in America’s warmest large city, and its coldest: Miami and Minneapolis respectively. The question isn’t an easy one: both air-conditioning and central heating systems use energy, but do they do so with comparable efficiency? One runs on electricity, the other sometimes on natural gas or oil. Even in Miami, people occasionally need to turn up the thermostat. Minneapolis, like any mid-Western city, can become uncomfortably hot, so both cities use both forms of climate control. The answer however proved to be quite straightforward.  Professor Sivak concludes that the cost of staying comfortably warm in Minneapolis requires 3.5 times the energy needed to stay cool in Miami. Miami’s advantage might be even greater, if only because humans tend to tolerate heat rather more good-temperedly than cold. “The traditional discussion of climatology and energy demand concentrates on the energy demands for cooling in hot climates,” Sivak writes. “However, the present results indicate that the focus should be paid to the opposite end of the scale as well.”- Climate News Network

FOR IMMEDIATE RELEASE Researchers may have found the way to a more comfortable life for suburbanites: garden lawns are more prolific carbon emitters than some farm crops, and keeping yourself warm uses much more energy than running an air conditioner. LONDON, 27 April – Here is some very limited advice on how to reduce your carbon footprint in suburban America: if you have a lawn, dig it up and plant a crop of maize. And if you live in Minneapolis, sell up and move to Miami. Two research papers in two journals have looked at two of those either/or questions that keep academics busy and dinner parties animated. Researchers at Elizabethtown College in Lancaster County, Pennsylvania, decided to look at what happens when farmland is converted to urban property. So for 10 weeks in the autumn of 2011, they visited and sampled the carbon dioxide release, soil moisture and temperatures, from urban lawns and from fields of corn, known also as Zea mays. They report in the Soil Science Society of America Journal that freshly mown grass sward won the dubious trophy for high greenhouse achievement. That is because lawns, on average, were hotter. “As you increase temperature, you increase biological activity – be it microbial, plant, fungal or animal”, said David Bowne, a biologist at the college. More biological activity meant more respiration, and more carbon dioxide releases. The higher lawn temperatures seem to be part of the urban heat island effect. Cities, notoriously, are much warmer than the surrounding countryside: roofs, roads, pavements and parking lots are dark, and absorb more sunlight, raising the ambient atmospheric temperatures overall. What the researchers had not quite expected, however, was to observe the effect on such a local scale. The research team found that urban development just 175 metres from a test location can cause an increase in temperature. The research is a small part of a much larger, global effort to understand what changes in land use do to climate.

Warmth is costly

  “If we go from one land use to another land use, how does that impact carbon cycling which in turn can affect climate change? Our study touches on one component of that cycle, and more research is needed to address this huge topic”, said Dr Bowne. Meanwhile, over at the University of Michigan, Ann Arbor, Michael Sivak asked himself the question: which demands more energy, air conditioning or central heating? He reports in Environmental Research Letters that he compared the costs of climate control in America’s warmest large city, and its coldest: Miami and Minneapolis respectively. The question isn’t an easy one: both air-conditioning and central heating systems use energy, but do they do so with comparable efficiency? One runs on electricity, the other sometimes on natural gas or oil. Even in Miami, people occasionally need to turn up the thermostat. Minneapolis, like any mid-Western city, can become uncomfortably hot, so both cities use both forms of climate control. The answer however proved to be quite straightforward.  Professor Sivak concludes that the cost of staying comfortably warm in Minneapolis requires 3.5 times the energy needed to stay cool in Miami. Miami’s advantage might be even greater, if only because humans tend to tolerate heat rather more good-temperedly than cold. “The traditional discussion of climatology and energy demand concentrates on the energy demands for cooling in hot climates,” Sivak writes. “However, the present results indicate that the focus should be paid to the opposite end of the scale as well.”- Climate News Network