By Ntsako Khosa
Portable HVAC equipment is slowly gaining traction both commercially and recreationally. We look at this aspect of the sector.
According to local suppliers of portable HVAC equipment, it is steadily becoming more popular. Mechanical engineer, Mpumzi Swana from Samac Engineering says, “The portable HVAC equipment market is a growing market in the country and this growth has led to various international companies introducing their portable products into the country”.
Such equipment can be used for a range of heat-related and comfort challenges year-round. Aggreko sector manager, temperature control, Kagiso Makgatho describes the equipment as mainly air conditioners used for:
- when the installed air conditioning system is under repairs, or
- it cannot cope with the load required.
“Chillers are used for temporary ice rinks or during the harvest period, chillers are also used for planned maintenance or shutdowns. They can also be used when there is an increase in load or demand on the current system. Furthermore, heat exchangers are used in temporary situations such as a breakdown on the equipment on site. While dehumidifiers are used to remove moisture from construction sites,” he says. Swana shares the same sentiments stating, “these can be used to provide air conditioning in venues that host events such as in tents or marquees and in server rooms. They also provide air conditioning in buildings that do not have fixed air conditioning units such as shops, small offices and/or homes.
“One of the main reasons why people purchase portable HVAC equipment is for its mobility. Portable units are useful in spaces where the occupants cannot or are not allowed to make physical alterations to a building,” Swana adds.
Portable HVAC equipment comes in different sizes and meets various requirements of the user. | Image credit: Aggreko
Back to basics
Swana details the definition of portable air conditioners as: “completely self-contained units, making them fully mobile and easy to set up in any room. Portable air conditioners are self-restricted air conditioning devices ideal for the cooling process in smaller areas, especially single rooms, bedrooms, computer rooms, dens, garages and other compact places. These air conditioning systems are placed on the ground and can be set up quickly with an installation kit. These models contain wheels, which facilitates with moving them to different rooms.”
The portable AC dates back to the 1940s, invented by American Robert Sherman. According to Swana, this was to meet the growing demand for household AC units.
“Most portable air conditioners are broken down into two categories based on their configuration as single hose or dual hose,” Swana shares.
Single-hose AC units use the same hose as both intake and exhaust for air. While single-hose units will still cool the space you’re using them in, they will have to work harder to do so, meaning they are not as efficient as a dual-hose air conditioner. On the plus side, they tend to be cheaper and are a perfectly adequate solution for smaller rooms, such as a small bedroom or studio apartment.
Dual-hose AC units have one intake hose and one exhaust hose. Because you have to separate the two hoses, these types of portable air conditioners are usually more energy efficient, generally cooling a room approximately 40% quicker than single-hose units, and they are the preferred choice if you’re looking to cool a larger room.
“Another popular portable unit is an air cooler which uses ice or cooled water to provide the thermal energy that is used to cool the air. These units use a technology known as evaporative cooling,” Swana says.
Types of equipment
“There are various types of equipment, chillers, air handlers, packaged air conditioners, dehumidifiers, fans, heat exchangers, cooling towers and water pumps. The list can be endless on what equipment can be portable,” Makgatho says.
Clark Michel from American-based company, Atlas Sales & Rentals says the market has three main types:
- Air-cooled portable air conditioners, which exhaust hot air through ductwork. Air-cooled portable air conditioners are the most commonly used equipment because they can be installed almost anywhere, usually in minutes. They are preferred over water-cooled units where water leakage, no matter how unlikely, would be catastrophic (e.g., in rooms that house computer servers).
- Water-cooled portable air conditioners, which connect to an external water source. They are best suited for use in facilities with central cooling towers or chiller systems or where the municipal water supply is plentiful and economical. Water-cooled systems do not require exhaust ducts, so they often are specified when there is no convenient way to exhaust hot air out of a room (e.g., in restaurants).
- Evaporative coolers, which use an internal or external water source to provide cooling and a fan to push air across a space. Although their performance is not comparable to that of portable air conditioners, they can provide a simple, low-cost cooling option for specialised use—most commonly, for outdoor areas where the budget or power supply is limited, as they can run on standard residential current. Warehouses are another common application for these units.
Portable HVAC equipment is often used on construction sites.Portable HVAC equipment is often used on construction sites. | Image credit: Pexels
Portable vs. fixed
The main difference between a fixed unit such as a split AC unit and a portable unit is that on a split unit, the condenser and the evaporator are separated with the condenser being placed outside rejecting the hot air and evaporator inside supplying the cool air. The portable unit is self-contained with both the condenser and evaporator compacted in one unit. A hose is attached to the back of the units to carry out the hot air from the condenser. This hose is usually taken out through a window.
“Portable air conditioners often use more electricity to cool the same square meter space compared to a split unit. This is mainly because they generate waste heat indoors instead of outside as the compressor is located inside the unit, creating more overall heat for the unit to deal with. Fixed units require certified installers to fit them into buildings. This results in extra costs making it expensive and less convenient for customers to install a fixed unit as compared to a portable unit which is a plug and play,” Swana explains.
“In terms of actual performance, the equipment is fairly similar. However, modifications are made to allow for easy movement, quick installation and in some instances, wheels placed at the bottom allow them to be moved. Other types have cages built around them to ensure they can be durable and also provide protection against theft and damage during transit,” Makgatho enlightens. Additionally, portable units have the same functions as spilt units like heating, cooling and humidity control. “As previously mentioned, the main advantage the portable unit has over the split unit is mobility,” says Swana.
Swana says that the key components that are used in portable air conditioners; include compressors, condenser and evaporator coils which act as heat exchangers, two fans for blowing cool air and extracting hot air, louvers which control the direction of the air and the electronics that control the functioning of the unit.
“An important component is the refrigerant. There are two main refrigerants that are found in portable air conditioners, these are R22 and R410A. R22 has traditionally been used over the decades but it is currently being phased out because of its negative impact on the Ozone Layer. R410 is eco-friendlier and more energy efficient,” he says.
Ice rinks are an area where portable HVAC equipment can be used.Ice rinks are an area where portable HVAC equipment can be used. | Image creit: Pexels
“Portable equipment is mainly used for temporary applications. It can be for a planned shutdown, to add capacity when the current equipment can’t cope with demand, or when there is a breakdown on the current equipment and so portable equipment is used in the interim,” says Makgatho. Increase in the use of portable HVAC equipment shows the potential that lies in it. Swana also attributes this to rising global temperatures. “People will be looking for convenient cooling solutions. Space and access to a convenient opening to extract heat are the key determinants of whether one should go for a portable unit. The size and configuration of the room is also a factor, if the windows are far from where the people are situated in a room a portable unit will not be as effective for cooling as a split unit,” he concludes.