Eight out of nine buildings guilty of energy wastage

Tuesday, December 25, 2007

NGO Greenpeace claimed that most of our existing infrastructure was actually a big menace as far as climate change goes. It claimed that eight of the nine buildings it surveyed at random in Delhi and Mumbai were guilty of energy wastage due to leakages on account of faulty design, use of inadequate insulating material and non-maintenance.

In a first of its kind exercise, these buildings were selected randomly for a thermographic test wherein their images were taken with a special infrared camera that was claimed to have captured the excessive energy leakage in them. The buildings included Mumbai Stock Exchange building in the financial capital and National Stock Exchange building, American Center and a five star hotel in Delhi. Officials of American Centre refused to comment on the exercise. A majority of buildings in our cities would meet the same fate.

Only the ITC building in Gurgaon could pass muster and was awarded the ‘Green Building’ tag.

K.Srinivas, climate and energy expert, Greenpeace India, said: “Our probe into the building sector in India has yielded startling results. Energy efficiency in the first important step to address India’s energy crisis and fight climate change. Our energy consumption can be halved by smart use of energy. The photos we have taken are indicative of the electricity wastage that a cross-section of our climate buildings are responsible for as well as the requirement for mandatory efficiency in the building sector.”

Thermography is a technology that shows temperature difference on the building surface area. A uniform temperature difference on the building surface means an environment friendly building. Temperature variations on the surface indicate that the cool air from inside the building is allowed to escape, implying that more energy is required to maintain the temperature inside the building.

In the past five years, the use of air-conditioning in India has been growing at the rate of almost 50% each year, according to figures made available by Greenpeace. Electricity consumption for air-conditioning in residential buildings has been about 7-10%, with a growth rate of consumption in the range of 15-20% per annum. Reduction in the leakage of cool air from buildings has the potential to reduce electricity consumption by over 40%.

According to a recent Inter-Governmental Panel on Climate Change report, the building sector also has a high level of electricity usage and hence the total emissions from this sector are very high. The report also states that energy efficiency in new and existing buildings in India can reduce carbon dioxide emissions by about 30% by 2030. The bureau of energy efficiency came out with a building efficiency code for new buildings in India in May 2007. However, compliance with the code is voluntary at present.

Deeksha Chopra

Times of India, 28th June,2007 Read more on this article...

The Pope condemns the climate change prophets of doom

Monday, December 24, 2007

The Pope condemns the climate change prophets of doom
12th December 2007
Pope Benedict XVI has launched a surprise attack on climate change prophets of doom, warning them that any solutions to global warming must be based on firm evidence and not on dubious ideology.

The leader of more than a billion Roman Catholics suggested that fears over man-made emissions melting the ice caps and causing a wave of unprecedented disasters were nothing more than scare-mongering.

The German-born Pontiff said that while some concerns may be valid it was vital that the international community based its policies on science rather than the dogma of the environmentalist movement.

His remarks will be made in his annual message for World Peace Day on January 1, but they were released as delegates from all over the world convened on the Indonesian holiday island of Bali for UN climate change talks.

The 80-year-old Pope said the world needed to care for the environment but not to the point where the welfare of animals and plants was given a greater priority than that of mankind.

Adrift: Polar bears on melting iceberg.

"Humanity today is rightly concerned about the ecological balance of tomorrow," he said in the message entitled "The Human Family, A Community of Peace".

"It is important for assessments in this regard to be carried out prudently, in dialogue with experts and people of wisdom, uninhibited by ideological pressure to draw hasty conclusions, and above all with the aim of reaching agreement on a model of sustainable development capable of ensuring the well-being of all while respecting environmental balances.

"If the protection of the environment involves costs, they should be justly distributed, taking due account of the different levels of development of various countries and the need for solidarity with future generations.

"Prudence does not mean failing to accept responsibilities and postponing decisions; it means being committed to making joint decisions after pondering responsibly the road to be taken."

Efforts to protect the environment should seek "agreement on a model of sustainable development capable of ensuring the well-being of all while respecting environmental balances", the Pope said.

He added that to further the cause of world peace it was sensible for nations to "choose the path of dialogue rather than the path of unilateral decisions" in how to cooperate responsibly on conserving the planet.

The Pope's message is traditionally sent to heads of government and international organisations.

His remarks reveal that while the Pope acknowledges that problems may be associated with unbridled development and climate change, he believes the case against global warming to be over-hyped.

A broad consensus is developing among the world's scientific community over the evils of climate change.

But there is also an intransigent body of scientific opinion which continues to insist that industrial emissions are not to blame for the phenomenon.

Such scientists point out that fluctuations in the earth's temperature are normal and can often be caused by waves of heat generated by the sun. Other critics of environmentalism have compared the movement to a burgeoning industry in its own right.

In the spring, the Vatican hosted a conference on climate change that was welcomed by environmentalists.

But senior cardinals close to the Vatican have since expressed doubts about a movement which has been likened by critics to be just as dogmatic in its assumptions as any religion.

In October, the Australian Cardinal George Pell, the Archbishop of Sydney, caused an outcry when he noted that the atmospheric temperature of Mars had risen by 0.5 degrees celsius.

"The industrial-military complex up on Mars can't be blamed for that," he said in a criticism of Australian scientists who had claimed that carbon emissions would force temperatures on earth to rise by almost five degrees by 2070 unless drastic solutions were enforced.

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Posted by Kaks at 8:28 AM 0 comments  

Calculation of U values through composite metal panel structures

Sunday, December 23, 2007

"Calculation of the heat loss through twin skin or composite panel metal construction brings
particular difficulties. Simplified methods are possible in some cases, but 2- or 3-dimensional
heat flow calculations must be carried out for some U-value and for all thermal bridge calculations. A number of software packages are available but many important decisions, which have a very significant effect on the results, are left to the user."

"Some standards, including BS EN 1252414, and the BRE U-values Conventions7 quote a conventional value of 50 W/mK for the conductivity of steel. The available information suggests that 60 W/mK is a more appropriate value for metal cladding systems. That value was used in the preparation of MCRMA Technical Note 143 and has been assumed in this guide."

The following steps are necessary to find the U-value,  (Omega)-value or f-value:

Details to be included in the model
a) Spacers – Section 5.1
b) Cladding rails - Section 5.3
c) Air cavities – Section 5.4
d) Profiles – Section 5.5
e) Fasteners - Section 5.6
f) Size of the model - Section 5.10


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Posted by Kaks at 2:06 PM 0 comments  

Albedo and Cool roofs

"Albedo includes the visible, infrared and ultraviolet wavelengths on a scale of 0 to 1. An albedo value of 0.0 indicates that the surface absorbs all solar radiation, and a 1.0 albedo value represents total reflectivity. EPA ENERGY STAR specifies an albedo of 0.65 or higher for low-slope roof applications and 0.25 for sloped roofs."

"Most roofing industry experts agree that a cool roof is one the exhibits a combination of high reflectivity and high emissivity."

"LEED version 2.2, released in October 2005, is the first national specification to use a relatively new measure of reporting a cool roof's properties. LEED 2.2 sustainable site credit 7.2 states that to receive one point, building owners should use a roof with a Solar Reflective Index (SRI) of 78 over at least 75% of the roof surface for roofs with slopes less than 2:12. The new twist is SRI, a unit developed by scientists at Lawrence Berkeley National Laboratory. SRI incorporates reflectivity and emissivity properties into one, easy to read, standardized measure so that roof buyers won't have to scratch their heads and try to figure our if a high reflectivity and low emissivity is better or worse than a medium reflectivity and high emissivity."

"SRI is calculated with a complex formula spelled out in ASTM E1980 and is a scale of 1 to 100 that is a measure of a roof's combined thermal properties. It is defined so that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100. But some hot roofs can have negative values, and some white thermoplastics and white roof coatings have scored as high as 104 to 100."

"SRI as a method for reporting cool roof data will probably take a little while to catch on. The Cool Roof Rating Council, an organization that verifies and labels cool roofing products has begun using the measure, while retaining reflectivity and emissivity measurements."

"The albedo of an object is the extent to which it diffusely reflects light, defined as the ratio of diffusely reflected to incident electromagnetic radiation. It is a unitless measure indicative of a surface's or body's diffuse reflectivity. The word is derived from Latin albedo "whiteness, in turn from albus "white".

"The term albedo (Latin for white) is commonly used to applied to the overall average reflection coefficient of an object. For example, the albedo of the Earth is 0.39 (Kaufmann) and this affects the equilibrium temperature of the Earth. The greenhouse effect, by trapping infrared radiation, can lower the albedo of the earth and cause global warming."

"The albedo of an object will determine its visual brightness when viewed with reflected light. "

"In more technical treatments of albedo, such as that of de Pater and Lissauer, a distinction is made between "bond albedo" and "geometric albedo", the numbers quoted above being geometric albedos. The geometric albedo is defined as the amount of radiation relative to that from a flat Lambertian surface which is an ideal reflector at all wavelengths. The bond albedo is the total radiation reflected from an object compared to the total incident radiation from the Sun. The bond albedo for the Earth is given as 0.29 by de Pater and Lissauer, compared to their value of 0.37 for the geometrical albedo."

ECBC U-value adjustment:

Cool Roofs:

"Roofs with slopes less than 20 degrees shall have an initial solar reflectance of no less than 0.70 and an initial emittance no less than 0.75. Solar reflectance shall be determined in accordance with ASTM E903-96 and emittance shall be determined in accordance with ASTM E408-71 (RA 1996)."

There seems to be no adjustment to the U value for a high albedo surface, unlike that available in some countries.

"The Roof/Ceiling U-value for buildings that are mechanically cooled and have a roof covering with a high-albedo surface can be increased in accordance with this section provided the roof surface:

a) has a minimum total solar reflectance of 0.75 when tested in accordance with ASTM E 903, and

b) has a minimum infrared emittance of 0.75 when tested in accordance with ASTM E408."

Ref: http://eetd.lbl.gov/coolroof/

For databases on properties of cool roof materials. Read more on this article...

Posted by Kaks at 1:51 PM 1 comments  

Some interesting features of the ECBC

(This may need a little mulling over!)

Orientation - The baseline (standard) building performance shall be generated by simulating the building with its actual orientation and again after rotating the entire building 90, 180, 270 degrees, then averaging the results. The building shall be modeled so that it does not shade itself.

Fenestration — Fenestration areas shall equal that in the proposed design or 40% of gross above grade wall area, whichever is smaller, and shall be distributed uniformly in horizontal bands across the four orientations. No shading projections are to be modeled; fenestration shall be assumed to be flush with the exterior wall or roof. Manually operated fenestration shading devices such as blinds or shades shall not be modeled.

Roof albedo - All roof surfaces shall be modeled with a reflectivity of 0.30

Ref: http://hareda.gov.in/ECBC.PDF (ECBC 2006)

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Posted by Kaks at 1:48 PM 0 comments  

Percentage savings in kW.hr/sqm/annum in an actual building in India.

Reference: http://www.indiaworldenergy.org/brochure/ECBC.pdf


"Most commercial buildings have (an) Energy Performance Index (EPI) of 200 to 400 kWhr/sqm/year in India."

"The average energy use for a typical commercial building is 200 kwh/square metre/year. Mandatory enforcement of the ECBC can reduce this to 120-160 kwh/sqm a year (a saving of 30-40 per cent)."


A typical office building: (Gurgaon)

Base EPI: = 186 kWhr/sqm/annum

After envelope optimisation: 165 kWhr/sqm/annum
After lighting optimisation: 120 kWr/sqm/annum
After HVAC optimisation: 98 kWhr/sqm/annum
After HVAC controls: 92 kWhr/sqm/annum
After daylight integration: 86 kWhr/sqm/annum

Reduction over base building due to envelope: = 11.3% (186-165)/186
Reduction over base building due to lighting: = 24.2% (165-120)/186
Reduction over base building due to HVAC: = 13.3% (120-98)/186
Reduction over base building due to HVAC controls: = 3.2% (98-92)/186
Reduction over base building due to Daylighting: = 3,2% (92-86)/186

That would mean a reduction in HVAC of 11.3% + 13.3% + 3.2% = 27.8%

and that for lighting; 24.2% + 3.2% = 27.4%

Total savings on account of HVAC and lighting alone: 27.8% + 27.4% = 55.2%.


Personal opinion:

That does seem rather high. Maybe that's because the base building itself had a thin wall, uninsulated roof, and extensive single glazing poorly oriented in the first place.

Considering the fact that around 57% of the energy in a typical Indian building is consumed by the HVAC system, and 16% by the lighting, seems that the envelope optimisation (which finally contributes to the HVAC load) could have been further optimised.


Or, the equipment load was very high :)

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Posted by Kaks at 1:11 PM 0 comments  

Sun Path diagrams

A great wiki on Sun-Path diagrams from Square-1. Has animated gifs.


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Posted by Kaks at 7:58 AM 0 comments  

The thermal matrix



Click the link for the interactive two-paned windows.

"The Design Matrix seeks to put the various elements of the building into context and aims to show how they can play a part in producing a successful design solution. A matrix of available solutions is provided with thumbnail sketches as a guide to the context. This matrix is backed by notes which give more detailed information and guidance in each area of concern.

The Performance Analyser allows the user to compare the impact of five different building 'elements' on indoor temperature and energy use:

* Thermal mass
* insulation
* window size
* window orientation
* window shading

Results are presented in the context of five different climates:

* London (cool)
* Athens (Mediterranian)
* Delhi (composite)
* Ahmedabad (desert)
* Trivandrum (hot-humid)

In each climate there are three alternative outputs:

* temperatures and comfort for an average summer day (choice a)
* a hot summer day (choice b)
* monthly energy use for heating and/or cooling (choice c)

Results are presented in two side-by-side windows so that the outputs from two different options can be directly compared. For details of the assumptions behind the simulations used in the Analyser please press the 'Parameters' button."

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Posted by Kaks at 7:48 AM 0 comments  

Analemma, the sun path

Courtesy: http://www.analemma.com

"The difference in time between what your watch reads and the position of the sun (clock time vs. sun time) is called the Equation-of-Time. If you are in the northern hemisphere and the sun’s position is to the east of where your watch indicates it would be, the Equation-of-Time is negative. If the sun is to the west, the Equation-of-Time is positive.

There is an easier way to see this effect. Find a place where the sun shines on the ground at noon all year long - winter, spring, summer, and fall. Place a rod about 3 feet tall into the ground, being very careful not to bump the end of it during the year. If you were constructing a sundial, this rod would be called a gnomon.

On the first day of each month, at the same time every day, (subtracting one hour if you are observing daylight saving time) place a mark with another shorter rod (you will need 12 of these) where the sun makes a shadow with the tip of the longer original rod. At the end of 12 months, you will see that the short rods make a figure-8 pattern on the ground.

Why does the sun take this strange path? There are two reasons and they are completely independent from each other.

1. The Earth is tilted on its axis 23.5° in relation to the plane of its orbit around the sun.

2. The Earth does not orbit the sun in a circle, but in an ellipse.

It is simply the sum of these two effects that causes the analemma.

It is hoped that with the aid of a few diagrams and animations, the analemma can be readily understood. "


Anthony Ayiomamitis of Greece, has the most beautiful images of the Analemma.


"Strange as it may seem, only seven times has someone ever managed to successfully image the solar analemma as a multi-exposure on a single piece of film. For those not familiar with the term, an analemma is the figure "8" loop that results when one observes the position of the sun at the same time during the day over the course of a year. Due to the earth's tilt about its axis (23.45°) and its elliptical orbit about the sun, the location of the sun is not constant from day to day when observed at the same time on each day over the course of a full year. Furthermore, this loop will be inclined at different angles depending on one's geographical latitude.

Since the analemma is considered one of the most difficult and demanding astronomical phenomenon to image, I immediately set out on such a marathon during the summer of 2001 by pursuing a complete set of analemmas from 08:00:00 to 17:00:00 UT+2 (hourly intervals) as well as the special case of the perfectly vertical analemma on the meridian (12:28:16 UT+2)." Read more on this article...

Posted by Kaks at 6:42 AM 0 comments  

24 Hour Sun, Arctic Circle

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Posted by Kaks at 6:05 AM 1 comments  

ECBC climate zones

Friday, December 21, 2007

Composite (Delhi)
Hot Dry (Ahmadabad)
Hot Humid (Kolkata),
Moderate (Bangalore)
Cold (Shillong)

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Glass, ECO-3 and CEPT

Extract from:


“Are all the technical specifications in the ECBC to the satisfaction of the glass industry? Maybe not,” says Satish Kumar, chief of party for India’s energy conservation program, International Resource Group, New Delhi. “However, instead of getting stuck on a number for SHGC [solar heat gain coefficient] and visual transmittance that will be acceptable to the industry, it should be realized that inclusion of aggressive technical specifications is an indication of the will of the government to make changes quickly. ECBC is likely to be in a voluntary mode for the next two to three years, which gives the glazing industry enough time to start gearing up for the mandatory phase of the ECBC.”

“The Commonwealth Games will be hosted in India in 2010 in New Delhi, and more than 400 new hotels will be built, along with several buildings to host the participants,” says Bipin Shah, international coordinator, National Fenestration Rating Council, Silver Spring, Md. “Due to low commercial building stock, there is a shortage of commercial space in New Delhi. Rents are five times than that in Washington D.C.”

However, like any other project, the code implementation comes with its share of problems. Padmanaban lists them: “Lack of trained professionals required to design compliant buildings; perception of increased first cost and delays that a project will have to face in order to be compliant with the ECBC; lack of availability of energy-efficient equipment and materials in the local marketplace; lack of equipment testing and certification; and institutional barriers in enforcing any codes.”

To overcome the issues, the USAID India is working with International Resources Group and its partners to implement an energy efficiency commercialization project, titled ECO 3. “We’ve been working with two, three states,” says Archana Walia, program management specialist, USAID India. “We’ll be developing an implementation plan for the chosen state, and it will need approval from the minister of power,” says Kumar, who is the chief of party of the USAID ECO3 Program.

The Center for Environmental Planning and Technology University in Ahmedabad, Gujarat, has been chosen to house the center of excellence. “The Center for Sustainable Environment and Energy in CEPT University will aim to integrate building design with energy-efficient practices, and bring the engineers, architects and designers up to speed with the latest technology for energy efficiency in buildings through training and workshops,” Shah says.

The land for the center will be provided by CEPT University and the fund for the building is expected to come from the state government. The All India Flat Glass Manufacturers’ Association will provide Rs. 2.5 crores, about $560,000, to buy the machines, Shah says. Sintex Industries, near Ahmedabad, a manufacturer of PVC doors, windows and modular furniture in India, has declared Rs. 1 crore support for CEPT University to start the energy center. This money is expected to be provided over the next five years. Karnataka already has such a center of excellence, Walia says.

http://www.glassmagazine.net/articles.php?id=724 Read more on this article...

Posted by Kaks at 10:37 PM 0 comments  

Wind Zones - India


(SVG file, nominally 1639 × 1852 pixels, file size: 349 KB). Click to enlarge.

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The Bottom Line

Saturday, December 15, 2007

The ones who scream and shout, are the ones who intend to profit the most. That, in a few words, is the economical history of mankind.

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Posted by Kaks at 9:40 PM 0 comments  

Global warming pact set for 2009 after US backs down

NUSA DUA, Indonesia (AFP) - A drama-filled 190-nation conference on Saturday set a 2009 deadline for a landmark pact to fight global warming after an isolated United States backed down on last-ditch objections.

UN Secretary General Ban Ki-moon hailed the so-called Bali Roadmap as a "pivotal first step" towards a new agreement for tackling the peril of climate change, after he had appealed to delegates to show flexibility.

Following gruelling all-night talks the conference launched a process to negotiate a new treaty that will take effect when the UN Kyoto Protocol's commitments expire in 2012.

The deal comes after a year of stark warnings from Nobel-winning scientists, who say that millions of people will be at risk of hunger, homelessness and disease by 2100 if temperatures keep rising at current rates.

The United States, the only major industrial nation to reject the Kyoto treaty, reached a compromise with the European Union (EU) to avoid mentioning any figures as a target for slashing greenhouse gas emissions.

The agreement instead only makes an indirect reference to scientists' warnings that the world must sharply cut back emissions to prevent what could be a catastrophic rise in temperatures.

But on an unscheduled 13th day of talks, the United States said it would not accept the statement as it wanted developing countries such as fast-growing China to make tougher commitments.

Senior US negotiator Paula Dobriansky said she had heard "many strong statements from many major developing country leaders on a greater role in helping to address urgently this global problem."

It "doesn't seem it's going to be reflected in our outcome here in the declaration," she said, telling the conference that the United States would reject the draft.

Dobriansky was loudly booed by other delegations. A US environmental activist representing Papua New Guinea said on the floor to rousing cheers: "If you're not willing to lead, please get out of the way."

After repeated verbal lashings, Dobriansky again took the microphone and said that Washington would "go forward and join consensus," to the cheers of the conference.

German Environment Minister Sigmar Gabriel, an outspoken critic of President George W. Bush's climate policy, said he was ready to ask through his mobile telephone for Chancellor Angela Merkel to intervene with the White House.

"I had already typed the SMS after Dobriansky's first statement but then I was able to cancel it," Gabriel said.

"In the end, nobody wanted to have a failure," including the United States, Gabriel said. "We have achieved more than we could have expected previously, but it is less than what is needed to meet the urgency of the problem."

The agreement came after extraordinary scenes in which the head of the United Nations jetted in to make a last-ditch appeal, the UN's exhausted climate chief nearly broke down in tears and chairman Indonesia apologised abjectly for a disastrous procedural mix-up.

"The Bali Roadmap that has been agreed is a pivotal first step toward an agreement that can address the threat of climate change, the defining challenge of our time," a statement from the UN chief said.

Alden Meyer of the US-based Union of Concerned Scientists welcomed the deal.

"What we witnessed today was an incredible drama," he said "I've been following these negotiations for 20 years and I've never seen anything like it."

Hans Verolme of conservation group WWF accused the world of bowing to US pressure and removing a scientific punch needed to fight global warming.

But he also said the Bali talks would inspire environmentalists and activist nations for climate-change negotiations until the end of President George W. Bush's mandate in January 2009.

"We have learned a historic lesson. If you expose to the world the dealings of the United States, they will ultimately back down," he said.

As activists speculated on whether the US U-turn was premeditated, US delegates said they believed from the reaction to their initial statement that developed countries would be serious about climate change.

"There is no question that we have opened a new phase in moving forward together," said senior White House aide James Connaughton. "The time had come to start a new chapter."

Bush has argued that the Kyoto Protocol is unfair as it does not require fast-growing emerging economies such as China, the second largest emitter after the United States, to meet targeted emissions curbs.

In a bid to break the deadlock, the proposed document ditched European calls for an "ambition" of the rich world to cut its emissions by 25 to 40 percent by 2020 from 1990 levels.

And there was no mention of a target of halving global levels of greenhouse gases by 2050 -- a goal that scientists say is essential to limiting the warming to around two degrees Celsius (3.6 degrees Fahrenheit).


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Posted by Kaks at 9:33 AM 0 comments  

Another inconvenient truth.

40% don't give a damn.

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Posted by Kaks at 8:51 AM 0 comments  

Technical Paper presented at ACRECONF 2007, Delhi, Hourly Load Calculation Analysis Programme for Indian Cities

Tuesday, December 11, 2007

Hourly Load Calculation Analysis Programme for Indian Cities

Vikram Murthy and Rajeev Kakkar, ISHRAE Mumbai Chapter

Rajeev Kakkar is a Technical Consultant (HVAC) by profession, a graduate from I.I.T Kharagpur, and has over 30 years of experience in the field. He is also the webmaster for http://www.hvacindia.com, the Technical advisor for the "Hourly Load Calculation Programme" sponsored by ISHRAE, and faculty for IIE, the "ISHRAE Institute Of Excellence" training programme series conducted by ISHRAE Mumbai Chapter.

Vikram Murthy graduated from IIT Kanpur in Electrical enginering in 1975 . He is Director of Univac Environment Systems Private Limited and Trustee of Tropical Airconditioning and Refrigeration Institute , a recognised Training Centre, for Technicians and Engineers. He has 33 years of diverse experience in leading HVAC Contracting Companies , is active professionally and socially , serving ISHRAE as the President of the Mumbai Chapter for 2007 - 2008 and The Rotary Club of Bombay Film City since 1992.


The ability to make sensible decisions regarding the HVAC design with respect to environment and economics is of utmost importance. Air-conditioning load calculations in India have been carried out using single day peak load manual calculations. The commercially available tools for load calculations are either too simple to be used for professional work (low-end packages) or too expensive with long and difficult learning curves. In a recently concluded research project, ISHRAE and ASHRAE India Chapter have developed a database of the hourly values of climatic parameters. The next step obviously was to develop an Hourly Load Calculation Programme.

Key words: hourly load calculation programme; HLCP; cooling loads; EnergyPlus; ECBC; building energy simulation; hourly weather data


Considering the fact that there is an urgent requirement of a validated HVAC sizing programme which uses BIS Design Day Standards and also provides hourly outputs using the heat balance equations found in EnergyPlus (and as adapted from BLAST), the development of HLCP as an ISHRAE project has been timely. The ability to make sensible and well-based decisions regarding not only the prediction of energy consumption in a building during the conceptual and design stage, but also to be able to finally size the HVAC system, both with respect to environment and economics, is of utmost importance.

Current Methodologies:

Currently, HVAC sizing loads is carried out mainly by manual and spreadsheet methods based on the de-facto standard of calculating instantaneous heat gains using methods developed by Carrier, and based on tabulated empirical ETDs (Effective Temperature Differences) for fenestration, walls and roofs, apart from a myriad of programmes developed by individuals, which have not really been validated. The current methodology also adopts use of design day weather data based on simultaneous peak occurrences of DB temperature and WB temperature, and whose validity and source is not known and has been lost in antiquity.

Weather Data:

In 1999 the Tata Energy Research Institute (TERI), http://www.teriin.org/ developed a set of hourly Indian weather data sets for 52 stations from measured sequences of climatic data from 1981 to 1992 based on the concept of "coincident" temperatures in line with and in the format as published in the ASHRAE Handbook of Fundamentals, 1997. With the availability of WeDCo hourly and DesignDay weather data, and with the virtually simultaneous availability of a stable version of the EnergyPlus simulation engine, an opportunity arose to create a cooling load programme using WeDCo weather data as an input to EnergyPlus.

As EnergyPlus is more of a "black box" with a shell for input, which is more suitable for research rather than day-today sizing calculations, it was logical to propose and deliver a HVAC sizing programme with a GUI to serve the needs of the community in India.

Interfaces and tools:

The commercially available tools so far for energy analysis and load calculations were either too simple to be used for professional work (low-end packages) or too expensive with long and difficult learning curves (high-end packages).

HLCP, hourly Load Calculation Programme:

HLCP is simplified zone-by-zone method for calculation of HVAC cooling loads for sizing of equipment specifically for Commercial buildings, based only on numerical inputs. HLCP uses the "Purchased Air" system type in EnergyPlus which is itself implemented based on the ASHRAE cooling sizing method and the cooling design load calculations are carried out using the standard ASHRAE Heat Balance method. That solves the issue of validation. HLCP is not just a graphical user interface for the EnergyPlus simulation engine; rather, it's an interface to calculate hourly loads. Post-processing of the data also takes care of the hourly latent loads. The user interface has been kept free of icons, with tabs and buttons in plain English, so that even the average HVAC engineer is able to use HLCP after a few trail runs. The interface has been designed as a tabbed wizard, again for ease of use, without unnecessary clutter of providing options which may really not be relevant for an HVAC sizing exercise.

HLCP can do what manual or spreadsheet HVAC sizing programmes cannot. That puts HLCP right in the path of the ECBC. In all likelihood, energy simulation interfaces built over EnergyPlus, such as DesignBuilder will be prominently used for compliance with the ECB code, during the Feasibility and Site Planning phase, and the Outline Design Phase of the building. During this stage, it would be necessary for the building to comply with the ECB code, and at this stage the Architect would have a much greater say than the HVAC designer. As the building design moves to the Scheme Design and from there to the Detailed Design, it is the HVAC engineer who will most likely call the shots.


On 27th May 2007, The Bureau of Energy Efficiency, India, BEE, released the Energy Conservation Building Codes ECBC, for Commercial Buildings. One of the clauses in the ECBC (apart from the clauses which specify the U values for walls, roofs and fenestrations), is that "The equipment capacities for the standard design shall be sized proportionally to the capacities in the proposed design based on sizing runs; i.e., the ratio between the capacities used in the annual simulations and the capacities determined by the sizing runs shall be the same for both the proposed design and standard design. Unmet load hours for the proposed design shall not differ from unmet load hours for the standard design by more than 50 hours."


This really means that it would be a wise step to compare the energy simulation loads with the design loads in parallel, as the building design moves from the feasibility and site planning stage to the detailed design stage, so as to ensure that this requirement of the ECBC is met without any ambiguity. The use of a building energy simulation programme in conjunction with HLCP, using the same weather data and the same simulation engine, in this case, EnergyPlus, would ensure compliance.

Further Information on HLCP can be found at: http://hvacindia.com/hlcp/


[1] ASHRAE Handbook of Fundamentals 1997

[2] Proceedings of the 23rd National Renewable Energy Convention, pp. 284-289,
edited by R L Sawhney, D Buddhi, and R P Gautam. Indore: Devi Ahilya
Extract: http://static.teriin.org/division/eetdiv/reta/docs/abs12.htm

[3] Review of Inside Design Conditions in Air Conditioned Spaces, by N. S. Hukmani, The
Air Conditioning and Refrigeration Journal, January 2004.

[4] Weather Data & Design Conditions For India,
booklet published by ISHRAE and AIC

[5] InputOutputReference.pdf, 2007
EnergyPlus documentation.

[6] Carrier Systems Design Manual

[7] Weather data - ISHRAE

[8] EnergyPlus: The Merger of BLAST and DOE-2, 1998 - Dru Crawley

[9] What outside Design Conditions should I use in calculating a heat load?

[10] ECBC 2007
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The Great Indian Building Simulation Race

Key sentence:

"Run it again"

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The Eagle...has landed!!

Saturday, December 1, 2007

Or maybe, HLCP has landed on the Eagle!

"Indian Interface to EnergyPlus: HLCP Hourly Load Calculation Program HLCP (Hourly Load Calculation Programme) is a graphical user interface for design-day and hourly load calculations for Indian cities, meant to be used with the EnergyPlus simulation engine. HLCP is a for-purchase program. For details, please go to http://www.hvacindia.com/hlcp/ "


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WINDOW and THERM (for thermal performance of fenestration)

WINDOW 5.2 is a publicly available computer program for calculating total window thermal performance indices (i.e. U-values, solar heat gain coefficients, shading coefficients, and visible transmittances). WINDOW 5.2 provides a versatile heat transfer analysis method consistent with the updated rating procedure developed by the National Fenestration Rating Council (NFRC) that is consistent with the ISO 15099 standard. The program can be used to design and develop new products, to assist educators in teaching heat transfer through windows, and to help public officials in developing building energy codes.


THERM is a module of the WINDOW+5 program under development by LBNL. WINDOW+5 is the next generation of the WINDOW software series and is being developed for the Microsoft Windows™ operating environment. THERM's results can be used with WINDOW's center-of-glass optical and thermal models to determine total window product U-factors and Solar Heat Gain Coefficients.

THERM is a state-of-the-art, Microsoft Windows™-based computer program developed at Lawrence Berkeley National Laboratory (LBNL) for use by building component manufacturers, engineers, educators, students, architects, and others interested in heat transfer. Using THERM, you can model two-dimensional heat-transfer effects in building components such as windows, walls, foundations, roofs, and doors; appliances; and other products where thermal bridges are of concern.

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