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HVAC/R and Solar energy engineering calculations


This website is a aid for beginning engineer and designer in the design of HVAC systems and solar thermal energy systems. In addition, the experienced engineer or designer may find this Website contents useful as a quick design reference guide and teaching tool.

This website allows you to navigate to groups of calculators we use in our programs and estimations of Heating, Ventilation, and Air conditioning, Refrigeration, Plumbing, Fire, building management systems and solar energy engineering development.  Feel free to use this resource.

The H in HVAC stands for Heating Systems which are used extensively in places with cold temperatures and climate. The heating systems are also of two types, Local systems and the Central Heating Systems.The local heating systems are the smaller individual units in various forms that are used to provide heat in smaller areas for e.g. portable electric heaters, wood stove and fire places etc. that are used commonly in most homes or even small offices/shops. However, all these systems are only suitable for smaller spaces like individual rooms.Larger spaces or commercial facilities like office spaces, hospitals, educational buildings,malls etc. require a larger heating system, which is provided by the central heating plant.At some places, the local systems may also be used to complement a central heating system. The heating process comprises of generation of heat, heat exchange with the air to be conditioned and distribution of the conditioned air in the facility. Thus, a typical central heating system will have three basic parts: the heating plant itself where fuel is converted into useful heat, a distribution system comprising of network of pipes/ducts to deliver heat to various spaces and controls to regulate the system. In a central heating system, heat source used may be a Furnace, a Boiler or a Heat Pump.

Ventilation (V of HVAC) is an important aspect of the HVAC systems. It is the process of exchanging, replacing or recirculating air in any space with the objective of maintaining the Indoor Air Quality (IAQ) and thus contribute towards the health and comfort of the occupants. Ventilation introduces outside air into the building thus replenishing oxygen and recirculating indoor air to prevent stagnation. This results in removal of unpleasant smells, excessive moisture, heat, dust, bacteria and gases like carbon monoxide and carbon dioxide from the atmosphere inside a facility.  All the equipment in a facility which handle/process air can be deemed to be part of the ventilation system. These could be standalone units or work in conjunction with other equipment. Heat exchangers, filtration units, supply and exhaust fans, humidifiers/dehumidifiers, the duct-work for carrying the air for distribution and delivery devices are all part of the building ventilation systems.

The Air-Conditioning traditionally referred to the cooling component of the HVAC systems, Air-Conditioning inadvertently becomes the right term to use. Once the concept of cooling is clear, the working of heat pump, will also become clearer since it only involves reversal of the flow of gas. Unlike the furnace and the boiler, which actually generate heat, the air-conditioning systems do not generate heat but just move the heat between inside the building and outside using the principles of thermodynamics. We know that heat energy will spontaneously flow from a warmer body/medium to a cooler body/medium. However, in order to make the heat move from a cooler body to a warmer body requires work to be done. This work is performed by the air-conditioning or refrigeration equipment.

Solar thermal energy is a form of energy and a technology for harnessing solar energy to generate thermal energy or electrical energy for use in industry, and in the residential and commercial sectors.

There are two main types of solar thermal systems for energy production – active and passive.  Active systems require moving parts like fans or pumps to circulate heat-carrying fluids. Passive systems have no mechanical components and rely on design features only to capture heat (e.g. greenhouses).  The technologies are also grouped by temperature – low, medium or high.


We try to follow reference standards and tables for equations, procedures and to permit the quick calculation of HVAC and Solar energy systems. But, we cannot guarantee that good outcomes always occur in respect to design criteria.

 We continuously update our references and software to assure that they have the most current data available to incorporate into our designs.



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