News | United CoolAir

September 13, 2019 by Matt Hanson

All about packaged units in air conditioning

Since the invention of the air conditioner in 1902, engineers have developed various ways of handling the HVAC process. The evaporator and condenser sections are the two major components of Heating, Ventilation and Air Conditioning (HVAC). This is the case as it applies to Direct Expansion (DX) type systems. At the same time, the indoor air absorbs heat inside the evaporator section. The condenser converts the vapor to a liquid by cooling it down. This section is usually located outside on the roof or on the ground. Because the two sections are located in different areas we call this a split system.

A packaged unit is when the heating and cooling components are contained in the same unit. This type of system can be beneficial when space is minimal. Many times, the placement of this type of HVAC is located outdoors but can also be installed completely indoors. Connected to both the supply and return air ducts; these operate similar to a central air system. The delivery of these packaged units can occur as both air-cooled or water-cooled systems.

The Refrigeration Cycle

In the refrigerant cycle, air-cooled or water-cooled liquid travels through an expansion valve where it converts to a vapor. The vapor then absorbs heat inside the evaporator before moving on to the compressor. After the compressor, the vapor then goes to the condenser where the refrigerant is air or water-cooled. The application of a heat exchanger component is installed with shell and tube; plate and frame, or coil.

The cooling effect is achievable by means of a continuous supply of water added to the system. Sometimes building codes do not permit an HVAC system to be installed outside. In this case, packaged units are installed as a solution. United CoolAir produces these all-indoor packaged systems. By the way, the self-contained HVAC units and are available with multiple air path configurations.

August 30, 2019 by Matt Hanson

What is a Heat Pump and how does it work?

A heat pump represents a growing segment of the HVAC industry. In practical terms, it is a reversal of how the air conditioning system works. While air conditioners are used to cool air; a heat pump can be used to cool or heat the air. This is especially true conditions are in place for this use. Therefore, it is necessary to employ a heat pump where temperatures are more moderate. The Summer months of the mid-south area of the United States contains the ideal conditions for this type of system. Conversely, they can be converted into a heating application when the temps are a bit cooler. In areas such as Florida or California where temperatures are mostly warm, it is best to use an air conditioner only.

The Heat Pump Refrigeration Cycle

Heat pumps use a reverse refrigeration cycle as opposed to the regular vapor compression cycle of an ac unit. Heat pumps use the condenser section to generate heat whereas an air conditioner uses it to reject heat. A heat pump uses a small amount of energy to move heat from one location to another. In a similar way it can cool a building or office space by working in reverse.

Air conditioners and heat pumps work in a very similar way. The biggest advantage to a heat pump is to negate the unit handling the separate loads of heating and cooling. Since the heat pump is only transferring heat it can operate by electricity. Additionally, the unit does not rely on the burning of fuel to accomplish the process.

In the cooler months, a reversing valve reroutes the refrigerant path making the outdoor condensing coil function as the evaporator. In a likewise manner the indoor coil serves as the condenser. The evaporator absorbs the outdoor heat and is in turn used by the condenser to heat the indoor space. However, there is one remaining problem. The outdoor evaporator absorbs heat and must operate at temperatures lower than the outside air. This low operating temperature causes ice to build-up on the outside of the evaporator. Finally, auxiliary heat is used during the defrost cycle to provide indoor heat during this stage.

August 1, 2019 by Matt Hanson

R22 Refrigerant is Set to Expire Beginning in 2020

What to consider for the coming year

Blog HVAC Pic R22

As we approach 2020, R22 (Freon) will be set to expire or use in the USA. Many facilities with outdated equipment won’t be able to purchase R22 to replenish a leaky system. For many years R22 was the HVAC industry standard until manufacturers began switching over R410a. The R22 refrigerant has been phased out due to the negative effect it as on the ozone layer. The scientific community has known since the 1970’s that Freon has a negative impact on the planet. The US Environmental Protection Agency has set the date of January 1, 2020, for R22 to longer to be manufactured or imported in the US. This poses a problem for how this will impact your commercial HVAC system.

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July 3, 2019 by Matt Hanson

The Thermal Expansion Valve (TXV) Explained

What you need to know about refrigerant flow

The Thermal Expansion Valve (TXV) is an important piece of equipment in the HVAC industry. The valve is used to control the amount of refrigerant released to the evaporator section. In this way it controls the difference between superheat and the current refrigerant temperature at the evaporator outlet. Therefore, This in turn keeps its saturation temperature at the current evaporating pressure stable. The Thermal Expansion Valve function is the control the flow of refrigerant into the evaporator in response to the cooling load. Additionally, TXV’s measure the superheat at the outlet and react to this by increasing or decreasing the amount of refrigerant flowing into the evaporator to try and maintain a constant superheat.

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June 18, 2019 by Matt Hanson

Commercial vs Residential HVAC Units

Learn the similarities and differences between commercial and residential units

Commercial and Residential HVAC units share many similarities but contain many differences as well. While some HVAC manufacturing companies produce units for both markets, others specialize in one or the other. The biggest differences have to do with size, and also whether the unit is a packaged or split system. Commercial systems are typically modular in nature, which makes them more flexible and expandable. These units are for business applications and can serve very large office buildings to small shops.

Many times, HVAC units are installed while the building is under construction which presents a problem later on. Eventually the unit will be in need of replacement. Commercial units because of their size and complexity usually require more highly trained technicians to install and service the equipment. These types of HVAC units are designed to serve multiple zones and is capable of providing heating as well as cooling to the building. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) sets Minimum Ventilation Rates in Breathing Zone standards as to how much fresh air must be delivered for the number of occupants in a given room. HVAC units are based on tonnage or CFM (Cubic Feet per Minute). While ASHRAE advises 20 CFM per person in a health club, libraries only require 5 CFM per each individual.

The Common HVAC Installation

HVAC systems usually contain an outdoor condenser section along with an indoor evaporator section. In a residential installation, condenser sections are mostly located on the ground and duct connected. Alternatively, in commercial applications the condenser section is usually placed on rooftops while the evaporator section is placed indoors. Both commercial and residential outdoor units can be susceptible to weather damage and vandalism. Residential units are also usually much smaller than commercial units but cannot be expanded. If more cooling capacity is needed, the unit must be replaced with a new unit. Companies that install HVAC equipment usually include both commercial and residential installs. Installers have a product line card where they sell HVAC units from several different brands.

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May 24, 2019 by Matt Hanson

Sick Building Syndrome and what to do about it

Sick or tight building syndrome is a term that describes from the ill effects building occupants suffer due to poor indoor air quality. Although not attributed to any specific disease (SBS), leads to a loss of employee productivity.