On an average a kid spends nearly 6hrs in school building, whereas an adult spends nearly about 9hrs in the air-conditioned office building which merely confines them into a closed space with the same repetitive circulation of the air.

Therefore, this urges the need of the fresh air for any individual. In fact in closed premises i.e. in a building we are subjected to forced air system i.e. air conditioners, which are responsible for the conditioning of the air in order to maintain the thermal comfort of the air. This air is reused by the air filters of the air conditioners. But they have a major impact as they are responsible for stopping the inflow of fresh air as it circulates the same air thus by altering or conditioning it.

The altering of the indoor air and stopping the fresh air to enter stops the supply of fresh air in the premises which further leads to various health issues such as nausea, asthma, sick building syndrome, headache, uneasiness etc.

In the race of feeling the best comfort, we tend to forget the quality of things in respect with nature that we should experience all together.  And therefore comfort air and quality air has to go hand in hand thus by maintaining a balance among them, as excess of either can lead to various imbalances which can further lead to various problems that are just not confined to the health problems.

With radiant systems, people are cooled by radiant heat transfer from their bodies to adjacent surfaces—ceilings, walls, or floors—whose temperatures are held a few degrees cooler than ambient. Space conditioning energy is usually moved from chillers or boilers to radiant panels or concrete slabs using water as a medium. This produces impressive savings, since water has roughly 3,400 times the energy transport capacity of air.
 

ADVANTAGES OF RADIANT COOLING SYSTEM:

Radiant cooling has numerous advantages over the forced air system i.e. air conditioners. And some of them are being listed as follows:

Firstly, Radiant cooling pipes may be embedded in floors, ceilings, walls or other exposed surfaces which marks the radiant cooling system as ADAPTABLE in nature and also gives ARCHITECTURAL FREEDOM from ducts, pipes etc.

Secondly, there is an Outdoor temperature sensor which is not exposed to direct sunlight which helps in the monitoring of the dew points and set points and therefore provides CONTROL over the system enabling the sensors to monitor the temperature and therefore helps in maintaining a comfortable temperature.

Thirdly, loads can be reduced by allowing a higher space set-point temperature and still maintaining the same level of cooling comfort compared to a traditional air handling unit (AHU) which gives in the EFFICIENCY not only in the terms of electricity but also in the terms of efficiency. The temperature of chilled water for conventional HVAC system is 7 degrees Celsius whereas it’s 16 degrees Celsius for radiant cooling system. Therefore, allowing chillers to use far lesser electrical energy to cool down water.

Fourthly, each cubic meter of water has a heat transfer capacity of 4200 KJ/K as opposed to 1.25 KJ/K of air. From these numbers, water is 3400 times more efficient at heat transfer than air used in conventional HVAC system. Hence, much lesser electrical energy consumption in pumping water for the same amount of cooling.

From the above data in terms of electrical consumption, radiant heating / cooling system saves about 30% of electricity as opposed to conventional HVAC system.

With the help of the radiant cooling the problems related with the altering the conditions of the fresh air cannot be changed.  Though the initial setting up of the radiant cooling is comparatively high as it involves several things but operationally it saves a lot of energy and efficiency of the resources. So in a long run this technique is workable and should be considered for long run technique.

Radiant energy to condition a space can be delivered at temperatures only a few degrees different from the temperature of the conditioned space. For cooling, it is important to maintain the temperature of the outer surface of the tubing that carries cooling water above the dew point to avoid condensation.

 

WHAT IS RADIANT COOLING SYSTEM?

A radiant cooling system is typically very much different from the forced air system i.e. air conditioners, VRV system, HVAC system etc.

A RADIANT COOLING SYSTEM refers to a temperature-controlled surface that cools indoor temperatures by removing sensible heat and where more than half of heat transfer occurs through thermal radiation.

Moving water is more efficient than moving air because of their physical and thermal properties. Water can carry 3,500 times the energy that air can carry for the same volume. This property of water is used to achieve maximum advantage in a radiant cooling system. Cold water flows through pipes embedded in the slab and cools the entire slab resulting in the slab surface being maintained at about 20 deg C.

Whenever there is a temperature difference between two objects, both objects will attempt to equalize the temperature. The energy transfer required to approach equivalent temperatures occurs through THERMAL COMFORT BASIC PHYSICAL PHENOMENA radiation, conduction and convection and this process of equalizing the temperature is known as radiant cooling.

• Reduced mechanical equipment foot print yields more usable   square footage.
• Intrusive ductwork may be reduced.
• Conditioning brought to space without the need for large ceiling plenum, leading to increased ceiling height, reduced building height or potential for additional levels.
• Thermal storage of the slab may allow off-peak cooling to augment a building‘s efficiency
• Flexible zoning through manifolds, actuators, and controls integrate perfectly with commercial building automation systems
• This produces impressive savings, since water has roughly 3,500 times the energy transport capacity of air.

 

PHENOMENON

Radiant cooling systems are using circulating water running in pipes in thermal contact with the surface which needs to be 2-4 degree below the desired temperature.

In this system, the water is circulated in the pipes which are being laid in the slab or are in the form of panels. Radiant cooling cools a floor or ceiling by absorbing the heat radiated from the rest of the room and removes sensible heat through radiant exchange with people and objects and not air. This not only saves electricity but also saves energy.

 

WHY RADIANT COOLING?

Radiant cooling has numerous advantages over the forced air system i.e. air conditioners. And some of them are being listed as follows:

Firstly, Radiant cooling pipes may be embedded in floors, ceilings, walls or other exposed surfaces which marks the radiant cooling system as ADAPTABLE in nature and also gives ARCHITECTURAL FREEDOM from ducts, pipes etc.

Secondly, there is an Outdoor temperature sensor which is not exposed to direct sunlight which helps in the monitoring of the dew points and set points and therefore provides CONTROL over the system enabling the sensors to monitor the temperature and therefore helps in maintaining a comfortable temperature.

Thirdly, loads can be reduced by allowing a higher space set-point temperature and still maintaining the same level of cooling comfort compared to a traditional air handling unit (AHU) which gives in the EFFICIENCY not only in the terms of electricity but also in the terms of efficiency.

 

A COMAPRISON…
When it comes to choosing between forced air and the quality air, what should be chosen?

Air conditioner system (forced air system) OR radiant cooling system (quality air system)?

Before we educate the individual about both the aspects, the major point to be considered is that both have their own pros and cons. And before choosing any of these one has to have the complete survey and then choose one.

1. EFFICIENCY
There is no use of ducts or pipes in case of radiant cooling and hence there are no duct losses enabling it to become more efficient in nature.
Whereas there is massive use of ducts and pipes in case of forced air conditioner system which can lead to various duct losses as well which marks it as less efficient.

2. COST
Radiant systems can lower building costs with the piping used for cooling incorporated into precast concrete flooring and the reduction of ceiling heights since only about 20% of the ducting is required as compared to traditional systems.
 Whereas in the traditional system a complete network of the ducting system has to be laid with proper ducting and pipes this automatically increases the cost.

3. TEMPERATURE AND COMFORT LEVEL/ ENHANCED THERMAL COMFORT
The temperature thus created by the air conditioners in the premises are uneven as keeping the temperature low can lead to chill atmosphere whereas keeping the temperature high can lead to humid or uneasy environment. Not only this but keeping the temperature as moderate can lead to loss in the efficiency and hence setting of the temperature is a task enabling it comfortable for everybody.
Whereas the temperature created by the radiant cooling system is comfortable as it is neither that high nor that low, moreover comfortable temperature with high efficiency is achieved.

4. AIRFLOW
A radiant system removes excess airflow and helps occupant’s cools down by absorbing their excess heat which enables in reducing the humidity from the atmosphere.
Whereas excess airflow in forced air system cannot be removed, this therefore can create an uneasy environment.

5. OVERCOOLING/EXTREME TEMPERATURE
In extreme summers or extreme winters, the effect of cooling and heating while entering into a building can be extreme in case of air conditioning system as the temperature being maintained is really high or low thus leading to spontaneous cold, headache and various other problems.
Whereas in the radiant cooling system the temperature which is being maintained is neither too high nor too low and therefore it turns out to be acceptable by the human body in terms of comfort level. Apart from this it helps one to rescue from various health issues.

6. INDOOR AIR QUALITY
Healthy indoor air quality is an important function of any comfort system. Forced air systems utilize air filters to improve the quality of air within a building.

The air circulated through the building via a series of ducts where the air filters are installed. The filters trap particles and airborne impurities returning cleaner air back into the building. 

A HVAC system will circulate a buildings entire volume of air several time a day ensuring air quality remains optimal.

 

ALL IN ALL..

It is clear to see that both means of cooling have their strengths. A forced air system is widely adopted making parts and professional installers readily available. Its versatility as both heating and cooling system in one and air purification make it an attractive option indeed.

Radiant conditioning systems however, seem to hold all the trump cards. With the drive to build better, greener buildings while providing occupants with optimal thermal comfort and keeping costs under control, it provides architects, engineers and owners with the perfect means to achieve the desired outcome.  

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