Heat Ventilation & Air Condition

  Guide to designing ductwork systems How to design a duct system. In this article, we’ll be learning how to size and design a ductwork system for efficiency. Methods of ductwork design There are many different methods used to design ventilation systems, the most common ways being: Velocity reduction method: (Residential or small commercial installations) Equal friction method: (Medium to large-sized commercial installations) Static regain: Very large installations (concert halls, airports, and industrial) We’re going to focus on the equal friction method in this example as it’s the most common method used for commercial HVAC systems and it's fairly simple to follow. Design example The Building Layout So we’ll jump straight into designing a system. We’ll use a small engineering office as an example and we want to make a layout drawing of the building which we’ll use for the design and calculations. This is a really simple building it has just 4 offices a corridor and a mechanical r...

  What is a heat exchanger? A heat exchanger is exactly what the name implies, a device used to transfer (exchange) heat or thermal energy. Heat exchangers are either given a hot fluid to provide heating or a cold fluid to provide cooling. A fluid can be either a liquid or a gas Heat always flows from hot to cold There must be a temperature difference for heat to flow How is heat exchanged? Thermal energy is transferred via three methods. Conduction Convection Radiation Most heat exchangers for HVAC purposes use convection and conduction. Radiation heat transfer does occur but it makes up only a small percentage. Conduction heat transfer Thermal image conduction heat transfer Conduction occurs when two materials of different temperatures physically touch. For example, we place a hot cup of coffee onto a table for a few minutes then remove the cup, the table will have conducted some of this thermal energy. Convection heat transfer Convection heat transfer Convection occurs when flui...