Mechanical – HVAC systems play numerous important roles in buildings, and without them, indoor spaces would quickly become uninhabitable. Mechanical – HVAC engineering allows for space heating, air conditioning, ventilation, tap water, wastewater drainage, elevators, and fire protection.

Mechanical – HVAC systems, on the other hand, are among the most expensive installations in modern buildings. They also employ bulky equipment that consumes more space than electrical and communication systems. A professional design from an MEP engineering firm is recommended to optimize the space requirements and costs of mechanical equipment.

HVAC systems are notable among mechanical installations for their high energy consumption. HVAC accounts for more than half of total energy consumption in many residential and commercial buildings. Energy efficiency measures implemented during the design and construction stages can significantly reduce the operating costs of HVAC systems in the long run.

HVAC systems are distinguished by their variety, and your building may have several viable options. Mechanical – HVAC engineers can assist you in selecting the best system for improving indoor air quality and energy efficiency.

Most ventilation and air conditioning systems are powered by electricity, but heating systems use a wider range of energy sources. Some heating systems are powered solely by electricity, but many others use fuels such as natural gas, heating oil, and propane. There are also space heating systems that run on biodiesel or biogas produced by the processing of organic waste.

Calculating the correct equipment capacity is a critical requirement in mechanical – HVAC design. Undersized equipment performs poorly, but oversized equipment wastes space and money. Smaller equipment with energy-saving measures may be possible in some cases.

• If the building insulation has a high R-value, for example, the heating and cooling equipment can be sized smaller.
• Effective insulation reduces heat loss in the winter and gain in the summer, allowing for a lower HVAC capacity.

Calculating mechanical loads using “rules of thumb” may appear to be a simple solution, but it frequently results in oversized installations. The equipment is more expensive than necessary, consumes more energy, and has higher maintenance costs. Professional designs require more complex calculations, but the benefits are significant: improved performance, cost savings, and energy efficiency.

Working with professional mechanical – HVAC engineers also results in faster project approval with the local building department.

Designs that adhere to “rules of thumb” are frequently rejected multiple times, delaying the construction stage. A professional design, on the other hand, is approved quickly, and construction can begin sooner.

• The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) is the industry authority on HVAC design in the United States. State governments use ASHRAE standards as a reference for mechanical codes, and they are also used internationally.
• Mechanical codes also include standards from organizations such as ACCA (Air Conditioning Contractors of America), ARI (Air-Conditioning and Refrigeration Institute), and SMACNA (Southern Mechanical Contractors Association) (Sheet Metal & Air Conditioning Contractors National Association).
• All building code standards are legally required in buildings, and the mechanical – HVAC engineers in charge of design must be well acquainted with them.

Because mechanical – HVAC systems consume a lot of energy, investing in energy-saving measures is highly recommended. The cost of some equipment and components may rise, but the long-term savings over the life of the building are many times greater.

The majority of the mechanical – HVAC design process in construction projects focuses on HVAC installations. These systems play an important role in buildings because they maintain a comfortable indoor temperature while supplying fresh air. HVAC systems also play a significant role in determining indoor air quality because they help regulate relative humidity and air pollution levels.

HVAC systems are distinguished by their diversity, and there may be several options for a given project. As with any design decision, there are tradeoffs, but a qualified engineering firm can recognize the equipment that usually works in your building.

Heating systems can be built to run on either fuel combustion or electricity. In both cases, there are several options, each with advantages and disadvantages.

Furnaces or boilers are commonly used in combustion-based heating systems. A furnace directly heats the air, whereas a boiler first heats water as an intermediate fluid. Steam boilers heat water until it evaporates, at which point the steam is routed to radiators to heat the indoor air. Hot water boilers, on the other hand, only raise the temperature of the water without evaporating it, and fan coils are used instead of radiators to heat the indoor air.

• Natural gas, propane, heating oil, biogas, and biodiesel are among the combustion heating fuels available.
• Historically, coal and wood were also used for space heating. However, many governments have banned these fuels due to their high pollution levels.
• In many places, heavy heating oils are also being phased out.

Only natural gas is delivered as a utility service among all the fuels available for space heating. All other fuels must be delivered to the building by truck and stored locally. As a result, natural gas is the most dependable option during emergencies such as extreme weather, because delivering other fuels may be impossible.

Resistance heaters or heat pumps are commonly used in electric heating systems. A resistance heater directs voltage to a heating element and circulates air to raise its temperature. A heat pump, on the other hand, operates on the same refrigeration cycle as an air conditioner, but in reverse to produce heating rather than cooling. During the summer, many heat pumps can be reversed and used as air conditioners.

• Heat pumps are far more efficient than resistance heaters because they require far less electricity to meet a given heating load.
• For every kWh of heat produced, a resistance heater must consume one kilowatt-hour of electricity. Most heat pumps, on the other hand, can produce between 2 and 4 kWh of heat for every kWh of electricity consumed.
• Ground-source heat pumps can generate more than 6 kWh of heat for every kWh of electricity consumed. They are also the most expensive, but they are easier to install in new constructions because they use buried pipes, which are more difficult to install in older structures.

Experienced HVAC engineers can recommend the best heating equipment for your building based on its features and needs. The local availability of fuel is also an important consideration.

Heat pumps are highly recommended to reduce your electricity bills if you plan to completely avoid fossil fuels. Unitary heat pumps can be used in different areas of your building, or a central unit can serve multiple areas.

Unlike space heating systems, which use a variety of energy sources, most air conditioning systems are powered by electricity. However, various types of equipment are available.

• Window air conditioners

Window air conditioners and packaged terminal air conditioners (PTAC) are similar in that they both contain all of the necessary components in a unit that is installed through the wall. These air conditioners, however, create an opening in your building envelope, reducing the effectiveness of insulation. They are typically the least expensive AC units, but they are also the least efficient – expect high summer electricity bills if your building uses window ACs or PTACs.

• Split type air conditioners

Split-type air conditioners, as the name implies, have separate housings for their condenser and evaporator. The condenser is located outside, while the evaporator is located inside, and both units are linked by an insulated refrigerant line. Split air conditioners are much more efficient than window ACs and PTACs because there is no gap in your window envelope.

• Packaged rooftop units or RTUs

Packaged rooftop units, or RTUs, are commonly used in low-rise commercial buildings and use air handlers connected to duct systems. A heat pump or an AC unit combined with a resistance or combustion heater can be used in a packaged unit to provide both heating and cooling.

• Chiller plants

Chiller plants are typically found in large industrial and commercial settings. Instead of directly cooling the air, chillers cool water that is then pumped throughout the building. The chilled water is delivered to fan coils, where it cools the indoor air. When dealing with vertical distances, chilled water piping is used because blowing cold air upwards is impractical and a waste of energy.