The air that Ibreathe
Intro: A leading chain of hotels, Ginger Hotel tookthe step of moving from window air-conditioners in their rooms to Variable FlowSystems that vastly improved not just the quality of air in the hotel rooms butalso the health of their guests and staff. AjitPanicker explains the design that his firm carried out at Hotel Ginger atAndheri, Mumbai.
“Any breakdownof the air-conditioning system leads to loss of revenue. Preventive maintenanceensures minimal breakdown and better energy efficiency.”
- AjitPanicker, CEO, Nova HVAC Systems, and President of theRefrigeration and Air-conditioning Trade Association of India.
If there is any industrythat has been affected badly by the Pandemic, it has been the hospitality industry.But, the recovery of this industry has been benefitting budget hotels whichhave lean operations and energy efficient systems.
Air-conditioning System
Systems for airconditioning need to control temperature, humidity and air quality withinpredetermined limits throughout the year. Suitability of system type cannot be generalized;it needs to be building –specific decisions considering initial cost,efficiency, maintenance, effect on building aesthetics, noise, service life,and other factors. Lower operating cost, central maintenance, and control areprimary considerations.
These systems oftenrequire a greater initial cost than normal one-to-one systems, but often resultin annual energy savings because additional benefits also include the abilityto reduce installed capacity by using load diversity. Centralized coolingsystems usually prove to be more cost-effective when the total building loadexceeds 100 TR, depending on climate and patterns of occupancy use. Here, wehave done a Variable Refrigerant Flow (VRF) System since this will be the bestoption in efficiency, performance, service life, and energy saving.
Ginger Hotel isair-conditioned with 216 HP VRF System. There are five nos x 42 HP VRF Systemand one nos. x 6 HP VRF System. Ground Floor has Ductable units for Lobby areaand Hi wall units for Back Office area. The First Floor has Ductable units forthe Live Kitchen and Restaurant area with one Hi wall unit for Staff cafe.
The Second Floorhas 16 Guestrooms with Hi wall Units. Ground, First and Second Floors areclubbed into one system of 42 HP Outdoor Unit. Also, DX Ductable units aregiven in Ground Floor Lobby and First Floor Restaurant area to ensure theseareas will be air-conditioned always even if one of the systems goes formaintenance.
From Second toTenth Floors, all floors were typical with 16 Guest Rooms having individual Hiwall units. Each two floors are connected to one 42 HP Outdoor Unit. I.e.,Third and Fourth Floors, Fifth and Sixth Floors, Seventh and Eighth Floors, andNinth and Tenth Floors are connected to 42 HP VRF Outdoor units. All OutdoorUnits of 42 HP are placed on the terrace and one 6 HP on the Service Floor.
The Refrigerantcopper tubing runs from all outdoor units to their indoor units through theshafts. The system is a floor wise system design to ensure occupancy per floorand optimum utilisation of each of the systems.
Basement Ventilation System
Ventilation is essentialin enclosed basement areas to dilute the level of toxic gases, such as carbonmonoxide (CO), oxides of nitrogen, presence of petrol/diesel fumes, and smokefrom engine exhaust. Carbon monoxide is a colourless, odourless and highlypoisonous gas. Even dilute concentrations of CO in air can cause nausea, headacheand vertigo.
The undesirable healthand fire hazard of the above contaminants can be contained if their levels are maintainedwithin permissible limits by ventilation. The basement ventilation system canbe classified as ‘supply-only, exhaust-only’ or a combination of the two.
Here, in theGinger Hotel project, we have installed 9000 CFM x 4nos for Exhaust Air TubeAxial fans for the parking area, in which two will be working in normal casesand the other two will be working in case of fire/emergency. The exhaust air istaken out through the exhaust duct running throughout the length. Fresh air isgiven naturally from louvers on the window side wall.
For DG room, 24,000CFM x 1 no Exhaust Air Tube Axial fan is given. For Pump room, we have given 3,500CFM Tube Axial Fan x 2 nos for Fresh Air and 3,500 CFM Tube Axial Fan x 2 nos forExhaust Air.
In the case of aPump room, one fresh air/exhaust fan will be working in a normal case and theother will be switched on automatically in case of fire/emergency. The fans areconnected to the Fire Panel/Building Management System to trigger the operationin case of fire. The exhaust ducts of DG room and Pump room run throughout thelength and are released outside.
Pressurization System
In buildingdesign, compartmentalization plays a vital part in limiting the spread of fireand smoke. The design should ensure avoidance of spread of smoke to adjacentspaces through the various leakage openings in the compartment enclosure, suchas cracks, openings around pipe ducts, airflow grills, and doors. In theabsence of proper sealing of all these openings, smoke and toxic gases willobstruct the free movement of occupants of the building through the exits.
Pressurizationof staircases, Lift well, Lobbies, etc., is of great importance for theexclusion of smoke and toxic gases from the protected exit. Pressurization is amethod adopted for protecting the exits from ingress of smoke, especially inhigh-rise buildings.
Inpressurization, air is injected into the staircases, lobbies, etc., asapplicable, to raise their pressure slightly above the pressure in adjacentparts of the building. As a result, ingress of smoke or toxic gases into the exitswill be prevented.
The systemconsists of the installation of a fan with an electric motor mounted in anisolated compartment. The outside air is captured through a shutter that has aparticle filter. The excess air is relieved through manual and automaticdampers properly calculated and installed at the suitable locations.
Here, we haveinstalled a Pressurization system for Staircase, Lift Well, and Lift Lobby. Allthe Pressurization fans are Tube Axial fans and are kept on the terrace floor. Fromthe terrace floor, we run the pressurization duct to each floor andcontinuously pressurize the staircase, lobby, and lift well areas.
15,000 CFMTubeAxial Fans x 2nos for Two Staircases, 5,500 CFM TubeAxial Fans x 3nos forLift Well Pressurization, and 3,500 CFM x 1no for Lift Lobby Pressurization areprovided which will be triggered in case of fire/emergency. These systems areindependent of other Building Ventilation Systems and are connected to theBuilding Management System for proper signal in case of fire/emergency.
Air Scrubber and Air WasherSystem for the Kitchen
An Air Washer isbasically a piece of equipment that is used to improve the quality of air. It doesso by scrubbing the air that moves inside it and then adjusting the humiditylevels in order to keep the environment consistent.
This works onthe principle of cooling outside air by passing it over water-saturated pads,causing the water to evaporate into it. The cool air is then directed into therequired space, and pushes warmer air out. Scrubber is an air washer with arefinement device which is used for cleaning kitchen fumes.
Air Washer Unit andAir Scrubber Units are installed here for the Kitchen on the First Floor. AirWasher unit of 8,500 CFM for Kitchen Supply Air and Wet Scrubber unit of 10,000CFM for Kitchen Exhaust air is used in the Live Kitchen at the hotel.
The units areplaced on the Service Floor above the First Floor and supply-exhaust ducts runfrom the units to the First Floor Kitchen. The exhaust duct from Scrubber is connectedto the Exhaust Hood over the burners. The kitchen fumes are drawn from thekitchen hood through the duct and enter the scrubber, flow horizontally and usewet/dry scrubbing to clean the same.
Toilet Exhaust System
Proper ToiletExhaust System should be done for exhausting the foul smell from the toilets. AtGinger Hotel, we have provided the Toilet exhaust system for all floors. ForGround and First Floors, we have individual exhaust systems.
On the Groundfloor, we have installed 1,000 CFM Exhaust fans for Ladies and Gents Changingrooms, and Restrooms. Also, small ceiling exhaust fans for individual toiletsfor Ground and First Floors. We exhaust the air from the toilet directlyoutside.
For the Typicalfloors from Second to Tenth Floors, we have installed all our Exhaust fans onthe terrace floor. There are nine sets of Exhaust Inline fans and the ductsfrom these fans are running to all floors.
From each floor,exhaust duct from one or two toilets will be connected to the main exhaust ductfrom the terrace floor. Here, we have 900 CFM x 6 nos, 850 CFM x 1 no, 450 CFMx 1 no and 400 CFM x 1 no Fans serving the toilets of all typical floors. 900CFM and 850 CFM fans are connected to exhaust ducts of two guestroom toiletsfrom a floor while 450 CFM and 400 CFM fans are connected to exhaust ducts ofone guest room toilet from a floor.
Maintenance and Support
Hotels are a24x7 application for HVAC systems. And, based on the occupancy these systems couldrun non-stop for months together. Any breakdown of the air-conditioning system leadsto loss of revenue. Preventive maintenance ensures minimal breakdown and betterenergy efficiency.
Nova uses state-of-the-arttechnology to manage a large team of field engineers for preventive maintenancecomplaint management, and spares management. An online cloud-based application –Pureblu – ensures the services management is always at its optimum levels. Breakdowncalls are attended to on the same day at the shortest possible time with thenearest available technician attending to the calls as soon as he receives thetrouble ticket on his phone app.
The entiremaintenance during the lifecycle of the machines is recorded real time forperformance and failure predictive analysis. This, along with Ginger hospitality,ensures a consistent comfort experience to the Hotel guests.
Theauthor is the CEO of Nova Group of Companies. He founded Pureblu Technologies.He is also the President of the Refrigeration and Air-conditioning TradeAssociation of India.