Active Air

Indoor air quality is a concern that building managers and building inhabitants have when they decide to investigate HVAC systems. 

Having your HVAC system cleaned is necessary for its overall lifespan. Over time they get dirty and have the potential to contain large amounts of dust and particles.

A great deal of contaminants and air pollutants can be generated in a regular building environment, including dust and chemicals. These contaminants are pulled into the HVAC system and recirculated on average up to 7 times per day. Over time, the re-circulation will cause a build up of contaminants in the ductwork.

Although a contaminated HVAC system doesn’t necessarily mean the air is unhealthy, the situation could be contributing to larger health issues or harbouring contaminants that, in the future, could cause serious problems for people with respiratory health conditions.

Benefits of HVAC Inspection

Always have your HVAC system inspected by a professional to conduct comprehensive examinations of components and systems to determine whether they are contaminated with a significant accumulation of particulate or microbial growth, or if HVAC performance is compromised due to contamination build-up.

This inspection will assess the cleanliness and structural integrity of an HVAC system by searching for obstructions, microbial contamination and any excess moisture.

Active Air can conduct HVAC inspections, as well as install new systems and repair and maintain existing ones. Call us on 020 3551 8936 to find out more. 

Air conditioning is great for all kinds of reasons – it keeps you cool when you’re too warm, it can warm you up when you’re too cold, and of course it’s the perfect place to hide when your lover’s husband arrives home from work early.

This Image was taken from the video of a naked man, clinging onto an eighth floor air conditioning unit, has been shared by an onlooker in China via video site LiveLeaks.

Speculation is rife that the naked man is hiding outside his lover’s apartment, due to their liaison being interrupted in the middle of the action. Although we don’t know how long this unfortunate Romeo was left dangling, we do know it’s not the first time that this exact same thing has happened in China.

Last year a man had to be rescued by firefighters after spending the night on a seventh storey ledge outside his lover’s window, because her husband had arrived home unexpectedly. He, too, was kept company by air conditioning – in this case he was sandwiched between two air con units.

Before we start advertising our air conditioning services to those conducting illicit affairs, it’s probably best we point out that this is not the best use for an air conditioning unit.

So, please, don’t start asking for advice on which type of unit to install for this particular purpose.

How can Heat be used for cooling? Well actually this isn’t something new.

In fact, the technology has been around for well over 100 years. For those that have forgotten (and indeed those that have never heard about) Absorption Chillers it should be borne in mind that you don’t always need to consider traditional Electric Vapour cycle equipment for your Commercial/Industrial Cooling projects!

Absorption Chillers have been around for a very long time, but for the last 20 years or so have fallen out of favour due to a number of factors, but all that is changing somewhat especially with different sizes and types being available especially where there is waste heat available – particularly in process cooling systems where this is common.

Without getting too technical, Absorption chillers use the thermal energy in hot water or steam to power a reaction that chills water to feed a central chilled water cooling system. This technology is time-tested and used in facilities around the world. In recent years, some of the advantages of absorption have become more prominent, making it a very attractive choice for applications where, 20 years ago, electric chillers were the rule.

Why then, are major energy users attracted to the absorption process?

Probably the major consideration is the operating costs of electric chillers which have increased dramatically over the last 10 years. Electric utilities not only have significantly increased energy rates, but also are increasing electric maximum demand charges.

In many commercial, industrial and institutional facilities, electric chillers make the single greatest contribution to those summer peaks, when demand charges are usually the highest. New electric chillers are more efficient, and certain other strategies can help reduce that demand contribution, but electric chiller demand is still a major contributor. CHP equipment is becoming more prominent and waste heat is often available. CHP Generators, especially gas turbines have great potential for by-product heat that can supply an absorption chiller with some or even all of its needed thermal input. The same CHP equipment that provides heat for the building(s) in the winter can also provide cooling in the summer.

As an energy saver you’ll be aware of how frustrating it is to see an industrial facility venting off steam because the boiler is continuously firing because there isn’t enough demand for the steam. If you were to use this spare capacity to supply an absorption chiller, not only would you avoid the need and cost of a dedicated boiler, but you could make the existing boilers to work more efficiently. The other alternative is by using natural gas as the thermal source. Modern equipment now allows alternatives.

Absorption chillers, have a relatively small electric demand when compared to conventional Chillers – just what’s needed for pumps and possibly cooling tower fans. An absorption chiller typically has electric demand less than 10% of its same-sized electric alternative. With rising demand charges, it can be a great energy/money-saving choice.

It is always essential to do a complete evaluation, and get help from a specialist who knows and understands absorption systems. The rules on equipment selection have changed from 20-years ago, and because of the wide variety available, many Consultants and Contractors now prefer the absorption option.

If you have a potential project, then we recommend determining the cost-effectiveness and suitability of absorption equipment by taking the following steps:

Conduct a plant survey to identify potential sources and availability of waste heat.

Determine cooling load requirements and the cost of meeting those requirements with existing mechanical chillers or new installations.

Obtain quotes for absorption chiller(s).

Undertake a life-cycle cost analysis to determine if the absorption chiller meets the cost-effectiveness criteria.

Active AIr, May 4th 2018 - call 020 3551 8936 if you would like to talk to oune of our enginners about your HVAC requirements. 

How does an air conditioner work?

An air conditioner’s job is to transfer heat from one place to another. In most cases, this means moving heat from indoors (and thereby cooling a room) to the outdoors, but the principle can also be reversed in order to heat an indoor environment.

This transfer is achieved by piping a special liquid called a refrigerant, which turns from liquid to gas at a very low temperature. This refrigerant is first sent through a series of coils, called ‘evaporator coils’. A fan will blow air over these coils, thereby cooling the room and warming the refrigerant within the pipes. This refrigerant then turns into a gas, which flows into another set of coils on the outside of the building called the condenser coils. Another set of fans then blows air over this set of coils, thereby dispersing the heat to the outside. Finally, a compressor squeezes the gaseous refrigerant so that it reverts to a liquid state. It is then piped through the evaporator coils and thusly the cycle continues.

How is cooling capacity measured?

The cooling capacity of an air-conditioning unit can be measured in tons. This measurement can trace its origins back to before air-conditioning was invented, when large blocks of ice were used to cool indoors. The amount of ice consumed by a refrigeration system in a single day would be up to a tons worth! Of course, we no longer use blocks of ice in our refrigeration, but the measurement remains. A ton is roughly equivalent to 12,000 British Thermal Units of cooling per hour.

What are the common causes of problems?

Since air conditioners are such complicated mechanical devices, there are a number of ailments which can affect them. Air conditioners are rated for a certain ‘load’ (the volume of air they are expected to cool) and are designed to carry a certain ‘charge’ (the quantity of refrigerant they contain). Straying outside these boundaries will place a strain on the system. Leaks in the refrigerant pipes, for example, will decrease the available charge and thereby reduce the air conditioner’s load capacity.

 What are filters for?

Filters are an important component of every AC system. They are placed just beside the evaporator coil, and their role is to remove tiny particulates from the air, ensuring that it is clean and thereby protecting the coil. Over time these filters can become clogged with dust and grime and the airflow will be restricted. For this reason it is important that filters are changed a regular intervals – particularly at times of the year where the system is being run regularly.

How can I maintain my AC system?

While simple maintenance like cleaning and filter-changing can be performed by a complete layman, air conditioners also contain a number of complicated mechanisms which might require the attention of a professional engineer.

How can I make the system more energy efficient?

The best way to ensure that an AC system run efficiently is to improve the energy-efficiency of the building it is placed within. This means installing double or triple glazing, sealing windows and leaky walls and insulating the roof. Anything which prevents heat from entering and escaping the building will reduce the workload of the AC unit, thereby increasing its longevity and reducing energy costs.

Why are ducts so important?

Larger air conditioning systems span many rooms and use a series of ducts to transport cold air outward from a centralized evaporator coil. This arrangement is vastly more efficient than a series of isolated units might be. However it is also dependent on the integrity of the ducts.

Leaking ducts will reduce the efficiency of the system. Also if the duct should happen to pass outside of the building – or through attics and garages – then the temperature of the air within it will be influenced. In order to preserve the temperature of the air flowing through the ducts, it is important that they are kept insulated and free from leaks.

How can I reduce the load on the AC system?

Repairing ducts and replacing filters are the two best ways of keeping the AC as robust as possible. But there are a few others steps which one might consider. Perhaps the most easily overlooked of these is to ensure that the airflow over the condenser coils is unrestricted. If there is a blockage, then the air around the coil can become stagnant. This prevents the coil from being warmed, which can in turn cause the refrigerant to freeze. This is a problem which will require costly maintenance!

Ventilation

So far we have looked at the air conditioner’s role in cooling an indoor environment. But that is not the only role they play: they can also act as heaters, as dehumidifiers and as ventilation systems. This role is an important one, since if the air within a home is not properly circulated, then it can lead to health problems – particularly in newer homes where walls are tighter.

Humidity

The modern air conditioners was first used to help to dry out the air in a Brooklyn printing plant. During hot summers in New York, the humidity was having a large effect on the results of the presses – by controlling the humidity, these variations were brought to a minimum. Unfortunately, modern air conditioners cannot independently control both temperature and humidity and so for more thorough control over conditions it is necessary to employ both an air conditioner and a separate dehumidifier.