Efficient planning and chosing the right equipment for heating, ventilation and air conditioning can save a property a lot on its energy spend finds Syed Ameen Kader
Hotels in India are fast realising the importance of having the right HVAC (Heating Ventilation and Air Conditioning) system in place to save on their energy spend. Though the HVAC system is not new to India the arrival of latest equipments and technology in the market will enable hoteliers to gain optimum result out of their HVAC system and save as much as 15-20% on energy costs without compromising on guests’ comfort.
Energy experts say there can’t be a set rule for all hotels as different hotels require different planning based on their demography, weather, designing of the building, materials used for the building and level of occupancy they expect.
“Since India has multiple climate zones and seasons, there is no copy paste solution for all hotels and each hotel building needs to be separately analysed for energy savings and efficient design opportunities. Efficient HVAC design is yet to catch up in India and a lot depends on the designers’ capability and interest,” says Hisham Ahmad, senior energy analyst with Environmental Design Solutions (EDS), a Delhi-based designing firm which provides consultancy service for green building.
It is very critical to have efficient planning in place for an HVAC system that begins at the designing stage of a building. There are many companies and LEED certified engineers who can help select the right system. One has to look at various aspects like type, size or number of chillers, cooling towers and even AHUs (Air Handling Units) required.
To gain optimum result out of the HVAC system, hoteliers must pay attention to three different aspects – designing, equipment installation and optimum usage.
The right building design also helps in optimising an HVAC system. “There is an urgent need in hotels to champion best practices for IAQ (Indoor Air Quality) in both new building design as well as renovation of existing facilities. Attention should be focused on the four key elements of ventilation, filtration, pressurisation and maintenance,” says Rahul Aeron, national sales head, DRI, a provider of fresh air solutions for the commercial and industrial markets.
Energy experts suggest that efforts should be made to minimise the usage of glasses for outer structure which have direct exposure to the sun. Even if the glasses are to be used, they could be put in a way which creates vacuum between two layers of glasses and help in deflecting the heat.
Many hotels use sandwich or DG glasses to reduce solar heat. Architects are also using sun films on the glasses for heat deflection.
Ahmad who is currently involved with over 30 green building projects says HVAC energy consumption cannot be viewed in isolation. “Efficient insulated envelope and a solar conscious design can reduce installed HVAC considerably.
Lighting also contributes directly to HVAC load and hence a well designed building with adequate day light and controlled lighting system reduces the installation and running energy costs.”
The load on an HVAC system could be minimised by taking some of the energy-saving measures such as appropriate insulation of heating and cooling lines to minimise heat gains or losses; usage of false ceilings and air curtains to optimise the effective space required air conditioning; usage of roof cooling, roof reflectance and efficient lighting.
The selection of high-efficiency HVAC units is the most important aspect and chillers come first in that as they account for maximum electricity consumption.
“Although these high-efficiency HVAC units may be more expensive than the average ones, the higher initial payment can be recovered through increased energy savings in as little as two to five years,” said an HVAC consultant. Choosing right equipment of right size is also very critical aspect, says Chandrakant Kumavat, assistant chief engineer of Renaissance Mumbai Hotel and Convention Centre.
Sharing his practical experience, Kumavat, says, “Previously, we had four chillers of 700 TR (Tonnage Refrigeration) each, two run by electricity and rest by gas. They would give us a total of 2800 TR but what if we don’t need that much TR at a time when requirement is low, for say, 1500 or 2000 TR. We would end up wasting lot of electricity. But now since we have chillers of different sizes —two 700 TR and four 350 TR, we get better utilisation of them and do lots of saving on electricity.”
Kumavat has also replaced his gas-run Vapour Absorber Machine (VAM) into centrifugal chillers and screw chillers which are run by electricity but give better performance for big hotels. “Though the gas-run VAM is cost effective but we prefer electric centrifugal or screw chillers as they give instant cooling.” He has managed to save about Rs1.5 crore last year through various such energy conserving measures.
There are a number of innovative products available in the market which are gaining fast acceptance in India due to their high energy efficiency features. Some of the players in India that have the best energy efficient products include Trane, Johnson Controls, Carrier and DRI besides others. They offer various energy efficient products for HVAC system which are highly successful worldwide.
“New hotels which are at the construction stage can opt for demand controlled ventilation (DCV), a product that conducts real-time measurements of the amount of carbon dioxide in the air at a given time and increases the amount of freshly ventilated air brought into a building based on the that measurement. This technique not only increases guest comfort but also reduces utility costs,” said Krishan Sachdev, director marketing and strategy, Carrier Airconditioning & Refrigeration Ltd. The company also offers energy efficient, non-ozone depleting Evergreen 23XRV variable speed water-cooled screw chiller which gives flexibility to reduce the load efficiency when facilities are in limited use.
At a time when hoteliers are looking at cutting their cost, asking them to upgrade to higher technology may not sound feasible to many as this will add to their cost. Sachdev says there are projects such as Clinton Climate Initiative (CCI) with whom Carrier has signed a memorandum of understanding to provide private building owners with access to financing terms to retrofit existing buildings with more energy-efficient systems in C-40 cities.
The C-40 is a group of the world’s largest cities who are committed to tackling climate change. India’s Delhi and Mumbai are part of that group.
Trane’s humidity control systems help providing ample ventilation with filtered and conditioned outdoor air. It monitors and controls the amount of moisture content in the air as per the requirement of the hotel building. “The biggest challenge faced by hotel owners is to maintain a high and consistent level of comfort which is critical in the lodging industry. Energy efficiency is the second-highest challenge that hoteliers face. However, energy efficiency should never be obtained at the price of guest discomfort,” said Pankaj Gupta, energy and environment leader, Trane India Pvt. Ltd.
Gupta shares an example of ITC Kakatiya hotel at Hyderabad. The property wanted to set an example as a leader in energy efficiency and environmental responsibility by focusing on implementing energy efficiency measures that included selecting the right HVAC systems and services.
“By retrofitting their old system with energy efficient systems from Trane, the hotel achieved improved HVAC system reliability and reduced energy consumption by more than 15% and is saving more than US $50,000 in reduced energy costs per annum.”
Johnson Controls’ heat pump is another energy efficient product which is a reverse cycle chiller that meets both heating and cooling needs of a hotel. “Use of heat pumps consumes 1/3rd the energy consumed by the boiler for heating applications,” said Pramoda Karkal, vice president and managing director, Building Efficiency, Johnson Controls.
“Most hoteliers find energy efficiency as an important subject and therefore when we present them with technologies such as variable speed drives (VSD), centrifugal chillers supported by energy modelling data, there is ready acceptance,” he added.
Treated Fresh Air Units (TFA) incorporating energy recovery devices provide many answers to the challenges faced by the designers today, said Aeron of DRI.
“They not only meet the need of energy efficiencies but also the better IAQ. TFAs are typically used for treating or preconditioning ventilation air i.e. fresh air as well as achieving acceptable IAQ, humidity control, energy efficiency, and in the process reducing the building envelope.”
Building Automation System and HVAC software are also widely used by hoteliers as they play crucial role in gaining optimum efficiency out of the HVAC system. “The Building Automation System helps us doing scheduling and temperature control of rooms according to our need. It has contributed significantly to our energy saving,” said Kumavat.
Indian hoteliers are becoming conscience of their environmental footprint and choosing equipments and systems that offer superior energy efficiency. Gupta says hoteliers, today, are willing to make an additional investment in to energy-efficient systems. A ‘green movement’ has emerged within the hospitality industry. According to Karkal, Indian hotelier is extremely intelligent and always willing to invest money provided the return on investment is high.
Hoteliers investing in energy efficient systems will not only project a “Green” image but also receive payback on their investments in a couple of years.
