Learn HVAC

 HVAC interview questions and answers 1.  What is ASHRAE &  ISHRAE?   American Society of Heating Refrigeration and Air-conditioning Engineers. Indian Society of Heating, Refrigerating and Air Conditioning Engineers. 2. What is COP and  Relative COP?  COP -  Coefficient Of Performance COP =Net Refrigeration Effect / Work Done Supplied It is the parameter on which efficiency is compared to air-conditioning units. It is calculated at 100% load. Relative COP =  ratio of actual COP and Theoretical COP 3.  What Is Btu? BTU = British thermal unit  It is the unit in which air-conditioning capacity defined. 1 TR = 12000 BTU/hr 4.Explain Refrigeration cycle?  Components that make a refrigeration system?. Watch the video with detailed explanation. 5. What Our Air Conditioning System and its function? and type of air-conditioning system? 6.  Which Gas used in   VRF? R410a 7. What is VRV and VRF?  htt...

  What Is Green Building Buildings or homes that are more energy-efficient, produce less waste and are healthier to be inside.  The main aim of the green building concept is to  -Save energy and water  -Reduce waste and reuse.  -Improve health and productivity -Use of material which is environment friendly. -Minimize the use of natural resource during the construction of the building.                        Watch vedio on #LEED HVAC design plays a very important role in getting leed certification. As HVAC is high power consuming service in the building and related to the air quality of indoor which can impact human. In India, multiple agencies are there for green building such as  -BEE (Bureau of energy efficiency) -IGBC ( Indian green building council) -Griha ( Green Rating for Integrated  Habitat Assessment) LEED   -The Leadership in Energy and Environmental Design (LEED) -I...

  C ontracts is a mutual or legal binding agreement between two parties based on terms and condition recorded in a document. It is the important document as it define the Scope of work, risk, duties and legal rights of both the owner and contractor. And we know executing the project is most complex activity and each activity have their own set of rules, that's why contracts is must between stakeholder involve in construction. It reduces the risk of dispute in future between client and contractor. Signed contract is legally valid and can be used in court when there is any dispute. Hence before signing any contract, please be clear on scope of work , clauses used in contracts and condition defined for executing the project. It is very rare in construction where project gets completed without any dispute , And when ever there is any dispute , contracts documents play important role to figure out disputes.   Types of Contracts  Based on industry, the following types of contra...

  The basic function of air-conditioning is to maintain the temperature, humidity and air quality in such a way that human feel comfortable.  But the initial cost and maintenance cost of the AC unit is higher and everyone can't afford it. So there is a need for an alternative, Air cooler or evaporative cooler fulfil this need. YouTube vedio for Air-Cooler -   A typical air cooler consists of a Fan, motor, water pump and cooling media as shown in the diagram. Entire parts are assembled in a container which opening.  From the front opening— air is forced in the room and air pulledf rom  remaining (side and back) opening. Warm air is pulled from atmosphere by a fan-operated by a motor, and it passes over wet pad i.e. cooling media and water absorbs the heat from the air causing the water to evaporate. The cool (moisturized) air supplied to the room for cooling. A small pump is used which pump water from the tank to in pad or cooling media. Ho ever the vapour formed...

Thermal Insulation   Thermal insulation is used in HVAC to avoided heat loss or heat gain from the duct of pipe. It also avoids condensation on cold surfaces. A heat-insulating material is one which has low thermal conductivity. Eg. 1. Duct carries chilled air from the AC unit to space, Heat loss or gain can change the temperature of the air  To avoid heat loss or gain, thermal insulation is used 2. Pipe  Chilled water pipe carrying water or refrigerant from one unit to other  to avoid Heat loss or gain, thermal insulation is used. Steam is generated in boiler and it is taken to the turbine through the pipe. To reduce heat loss or gain, insulation is used. Required Property on Insulating material 1. Can withstand high or low temperature 2. Should have a long life and can not be easily damaged. 3. Easy to install. 4.Should be economical. 5.Fire resistance. 6. resistance to Ozone and UV. Various material such as asbestos, glass wool, expanded polystyrene, puff, ni...

  TR        -       Tons of Refrigeration - It Is a unit of refrigeration. -The rating of a refrigeration machine is given by a standard unit of refrigeration called Ton of Refrigeration. -One a ton of refrigeration (1TR) means the capacity to freeze 1 ton of water from and at 0’ in 24 Hrs. It's important to note that the freezing or melting of the ice represents a change-of-state only, which is considered a transfer of latent heat, as opposed to a change in temperature which is a transfer of sensible heat . Calculation • In USA 1 ton is taken as 2000lbs and its latent of fusion 144 B.Th. U/ lb  (334.9 KJ/Kg).                1 TR = (2000x144)/24                         = 12000 B  Th  U/ hr        ...