Engineering & Knowledge

Fundamentals & Engineering

Pump Construction (Part1)

In 1689 the physicist Denis Papin invented the centrifugal pump and today this kind of pump is the most used around the world. The centrifugal pump is built on a simple principle: Liquid is led to the impeller hub and by means of the centrifugal force it is flung towards the periphery of the impellers. The construction is fairly inexpensive, robust and simple and its high speed makes it possible to connect the pump directly to an asynchronous motor.

Expansion Valves Selection

The expansion valve regulates the amount of compressed liquid refrigerant moving into the evaporator. It removes pressure from the liquid refrigerant to allow expansion or change of state from a liquid to a gas in the evaporator. In order to properly select Expansion Valves one should pay attention to the items that we mention in this post.

What Is Corrosion?

Corrosion is usually referred to as the degradation of the metal by chemical or electrochemical reaction with its environment, see figure 1. When considered broadly, corrosion may be looked upon as the tendency of the metal to revert to its natural state similar to the oxide from which it was originally melted. Only precious metals, such as gold and platinum are found in nature in their metallic state. – Types of corrosion – Uniform corrosion – Pitting corrosion – Crevice corrosion – Intergranular corrosion – Selective corrosion – Erosion corrosion – Cavitation corrosion – Stress corrosion cracking (SCC) – Corrosion fatigue – Galvanic corrosion

Water Hammer (Part1)

Under unfavorable circumstances, damage due to water hammer may occur in pipelines measuring more than one hundred meters and conveying only several tenths of a liter per second. But even very short, unsupported pipelines in pumping stations can be damaged by resonant vibrations if they are not properly anchored. By contrast, the phenomenon is not very common in building services systems, e.g. in heating and drinking water supply pipelines, which typically are short in length and have a small cross-section.

Water Tube Versus Fire Tube Boilers

Water tube boilers and fire tube boilers are two different types of steam boilers that are commonly used in industrial and commercial applications. Both types of boilers use a system of tubes to generate steam, but they differ in the way that the tubes are arranged and the way that the hot gases from the burner pass through the tubes.

Capillary Tube Refrigeration

A refrigeration capillary tube is a small, narrow tube that is used in refrigeration systems to control the flow of refrigerant. It is typically made of copper or other highly conductive metal, and is used in conjunction with a compressor, evaporator, and condenser to transfer heat from one location to another. The capillary tube is placed between the evaporator and the compressor in the refrigeration system, and it acts as a metering device to control the flow of refrigerant.

Refrigeration Formulas and Calculations

These formulas are commonly used in the field of refrigeration and air conditioning to calculate various performance parameters of a refrigeration system such as compression work, compression power, coefficient of performance, net refrigeration effect, capacity, compressor displacement, heat of compression, volumetric efficiency, and compression ratio. These formulas are based on the thermodynamics principles and are generally used to evaluate the performance of the refrigeration system and to optimize its design.

The coefficient of velocity (Cv)

Cv, or coefficient of velocity, is a measure of the flow capacity of a valve. It represents the number of gallons per minute (GPM) of water at 60°F that will flow through a valve with a one-inch opening at a pressure drop of one pound per square inch (PSI). Cv can be calculated using various formulas, such as the one based on water at 60F and one that takes into account the specific gravity of the fluid. Cv is a theoretical value and it may vary depending on the actual conditions of the valve. When selecting a valve for a specific application, it is important to consider the Cv in relation to the flow rate and pressure drop requirements of the system, as well as other factors such as ease of maintenance, cost, and safety.

Pipe Insulation Guideline

Pipe insulation is crucial for maintaining energy efficiency, temperature control, condensation control, noise reduction, and safety. ASHRAE provides specific thickness recommendations for different pipe sizes and temperature ranges in its standard 90.1. When selecting pipe insulation based on ASHRAE standards, it’s important to consider the temperature, pipe size, environmental considerations, fire resistance, and energy efficiency.

Refrigerant Piping – part2

In this post, we will be continuing our comprehensive training on how to size refrigerant piping. We will cover all the important aspects of this process, including determining the pipe size, pressure drop, and other factors. We will also discuss topics such as sizing refrigerant lines, equivalent length for refrigerant lines, and how to determine equivalent length. With this training, you will have the knowledge and confidence to size refrigerant piping accurately and correctly in any situation.

HVAC Ventilation Design: Exhaust Air Ventilation By Rate and ACH

Complete guide to HVAC exhaust air ventilation design using ASHRAE, CIBSE, and Carrier standards covering rate calculations, ACH requirements, and specialized applications for effective contaminant removal and energy efficiency.

HVAC Ventilation Design: Outdoor Air Ventilation By Rate and ACH

Complete guide to HVAC outdoor air ventilation design using ASHRAE, CIBSE, and Carrier standards covering rate calculations, ACH requirements, and building-specific applications for optimal indoor air quality.

HVAC Ventilation Design: Indoor Air Quality and Air Contaminants

Complete guide to HVAC indoor air quality and air contaminant management using ASHRAE, CIBSE standards covering contaminant identification, control strategies, and advanced treatment technologies for healthy indoor environments.

HVAC Ventilation Design: Air Intake Minimum Separation Distance

Complete guide to HVAC air intake minimum separation distances using ASHRAE 62.1 standards covering contamination source requirements, measurement methods, and compliance strategies for optimal outdoor air quality protection.

HVAC Ventilation Design: Air Classifications

Complete guide to HVAC air classifications using ASHRAE 62.1 and CIBSE standards covering air quality categories, contamination levels, filtration requirements, and ventilation strategies for optimal indoor environmental control.

HVAC Ventilation Design: General Schematic and Equations

Complete guide to HVAC ventilation design using ASHRAE 62.1 standards covering calculation procedures, system schematics, and modern ventilation strategies for optimal indoor air quality and energy efficiency.

HVAC Load Estimation: Fouling Factor

Complete guide to fouling factors in HVAC load estimation using Carrier water conditioning standards for accurate heat transfer equipment sizing and comprehensive water quality management strategies.

HVAC Load Estimation: Diversity Factor

Complete guide to diversity factors in HVAC load estimation using CIBSE and Carrier standards for accurate system sizing that reflects realistic building operation patterns and prevents equipment oversizing.

HVAC Load Estimation: Indoor Design Conditions and System Requirements by Building Type

Complete guide to indoor design conditions for HVAC load estimation covering temperature, humidity, air quality, and specialized requirements for residential, commercial, industrial, healthcare, and specialty building applications using ASHRAE, CIBSE, and Carrier standards.

HVAC Load Estimation: Infiltration Heat Gain and Loss

Complete guide to infiltration in HVAC load estimation using ASHRAE, CIBSE, and Carrier standards for accurate assessment of uncontrolled air exchange and its impact on heating and cooling loads.

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Download Weather Design Conditions (ASHRAE)

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