Engineering & Knowledge - HVAC-R & Solar Engineering Resource

基础与工程

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.

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

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.

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.

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.

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

在这篇文章中，我们将继续进行有关如何确定制冷剂管道尺寸的全面培训。我们将涵盖该过程的所有重要方面，包括确定管道尺寸、压降和其他因素。我们还将讨论制冷剂管路尺寸、制冷剂管路等效长度以及如何确定等效长度等主题。通过本培训，您将拥有在任何情况下准确、正确地确定制冷剂管道尺寸的知识和信心。

以前

标准与合规性

HVAC 通风设计：按速率和 ACH 进行排气通风

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 负载估算：多样性因素

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 负荷估算：按建筑类型划分的室内设计条件和系统要求

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 负载估算：渗透热增益和热损失

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.

以前

数字工具和资源

Belimo SelectPro – 免费下载

免费下载 SelectPro 桌面应用程序。使用导出构建器、报价生成器和集中参考文档来调整和选择阀门、执行器和传感器。适用于 HVAC 工程师和承包商。

常见管道材料的热膨胀率

使用我们的交互式计算器轻松计算常见管道材料的热膨胀率。获取金属和塑料的准确数据、设计见解和可操作的表格，这对于关注系统可靠性和能源效率的 HVAC 工程师、设计师和顾问至关重要。

暖通空调设备预期寿命计算器

我们创建了专业的暖通空调设备预期寿命计算器。该应用程序提供了全面的计算，用于确定各种 HVAC 设备类型的剩余使用寿命。

适用于现代 HVAC 应用的 BIM 软件解决方案

As the HVAC industry continues to evolve in 2025, Building Information Modeling (BIM) has become an indispensable tool for professionals seeking to optimize design, installation, and maintenance processes. For HVAC engineers, contractors, and technicians, selecting the right BIM software can significantly impact project efficiency and outcomes. Let’s explore the most effective BIM solutions for HVAC applications.

McQuay软件下载

McQuay (As part of Daikin Industries) is one of the largest air conditioning, heating, ventilating and refrigeration companies in the HVAC/R industry. Therefore, we decided to make some softwares that this company has introduced to the industry based on their experience and knowledge available for download.

暖通空调职业机会

The HVAC/R (heating, ventilating, and air conditioning / refrigeration) industry is rapidly changing due to advancements in technology being spurred on by the need for increased energy efficiencies. Accordingly, the career opportunities open to an individual seeking employment in HVAC fields can be divided roughly into four categories, each dependent upon a different type or degree of education and/or training.

工程与知识