SPBRC410 P-HC-BRC41000000 控制器模块 ABB Bailey
e类似地，仅在HVAC温度中的汽相
范围内，水在相同温度下会发生状态变化
或者在基于温度的相同压力范围内。在人体舒适温度范围内
人和环境质量对健康、结构和环境的影响，
而对于材料的保存也与水分有关
*另见19章。
暖通空调工程基础：1部分
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暖通空调工程基础：1部分9
空气。湿空气条件的控制是
暖通空调系统。记住以下几点：
当水在给定温度和大气条件下蒸发到空气中时，空气被视为水分饱和
压力被水蒸气同时凝结到
液体饱和空气的冷却会导致露水、雾、雨或雪。
暖空气比冷空气能保持更多的水分。
相对湿度百分比测量空气中有多少水蒸气
与空气饱和时的空气量相比
在相同的温度下。形容词“相对”是合适的，因为空气所能容纳的水的量是相对的
温度和大气压。与海拔或天气条件相关的气压变化会影响
空气的保湿能力。
湿度图，显示以下混合物的特性：
单图上的湿空气是定量分析的有用工具
计算和分析HVAC过程。熟悉和熟练
暖通空调设计师必须使用这些图表。
不可能在热交换中从空气中除去水分
不使空气接近饱和线的冷却过程。
水分可通过干燥剂去除，而不会接近饱和。
人类健康和舒适的佳条件范围为70
至75华氏度和40至50%的相对湿度。就感知而言
舒适度，相对湿度稍高可抵消稍低
环境温度。
寒冷气候下的潮湿空气是一个问题，也是建筑物的一个责任
设计师。因为内部环境通常比
需要外部空气、绝缘和蒸汽屏障，以防止
结构空腔中的冷凝。不遵守这一责任可能导致建筑物的早期损坏。游泳池
加湿建筑物（医院等）尤其脆弱。关于本主题的进一步讨论，见参考文献6和19章。
1.9声音和振动*
声音和振动已成为暖通空调领域的一个热门话题
设计师，不是说它们是主要加热、冷却和
*另见20章。
暖通空调工程基础：1部分
下载自数字工程图书馆@McGraw-Hill（www.digitalengineeringlibrary.com）
版权所有©2004麦格劳-希尔公司。版权所有。
任何使用均受网站上给出的使用条款的约束。
10.一章
空调功能，但因为它们是次要因素
如果处理不当，可能会破坏其他成功的
暖通空调安装。
所有声音和振动都是动能的形式
暖通空调世界它们通常来源于移动设备，移动
空气、减压设备或其他移动流体。问题
HVAC系统部件产生噪音或振动时发生
在有人居住或过程敏感的空间内或附近。如果产生的声音或振动水平超过当地公差水平
暖通空调系统被视为不合格。
对于暖通空调系统而言
SPBRC410 P-HC-BRC41000000 控制器模块 ABB Bailey
SPBRC410 P-HC-BRC41000000 控制器模块 ABB Bailey
e similarly in only a vapor phase in the HVAC temperature
range, water will undergo a change of state in the same temperature
range based on pressure, or in the same pressure range based on temperature. In the human comfort temperature range, the comfort of
people and the quality of the environment for health, for structures,
and for preservation of materials are also related to the moisture in
*See also Chap. 19.
HVAC Engineering Fundamentals: Part 1
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HVAC Engineering Fundamentals: Part 1 9
the air. Control of the moist-air condition is a primary objective of the
HVAC system. Remember the following:
Air is considered to be saturated with moisture when the evaporation of water into the air at a given temperature and atmospheric
pressure is offset by a concurrent condensation of water vapor to
liquid. Cooling of saturated air results in dew, fog, rain, or snow.
Warm air can hold more moisture than cold air.
Percent relative humidity measures how much water vapor is in the
air compared to how much there would be if the air were saturated
at the same temperature. The adjective relative is appropriate because the absolute amount of water that air can hold is relative
to both temperature and barometric pressure. Changes in barometric pressure related to altitude or to weather conditions affect the
moisture-holding capacity of air.
A psychrometric chart which presents properties of mixtures of
moist air on a single graph is a most useful tool for quantitatively
calculating and analyzing HVAC processes. Familiarity and facility
with these charts are a must for the HVAC designer.
It is impossible to remove moisture from air in a heat exchange
cooling process without bringing the air near to the saturation line.
Moisture may be removed by desiccants without approaching saturation.
Optimum conditions for human health and comfort range from 70
to 75F and 40 to 50 percent relative humidity. In terms of perceived
comfort, a little higher relative humidity can offset a little lower
ambient temperature.
Moist air in cold climates is a problem and a liability for building
designers. Since the inside environment usually is moister than the
outside air, insulation and vapor barriers are required to prevent
condensation in the structural cavities. Failure to respect this liability may lead to early deterioration of a building. Swimming pools
and humidified buildings (hospitals, etc.) are particularly vulnerable. See Ref. 6 and Chap. 19 for further discussion of this topic.
1.9 Sound and Vibration*
Sound and vibration have become a topic of interest for the HVAC
designer, not that they are part of the primary heating, cooling, and
*See also Chap. 20.
HVAC Engineering Fundamentals: Part 1
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Any use is subject to the Terms of Use as given at the website.
10 Chapter One
air conditioning functions but because they are secondary factors
which, if not properly handled, can destroy an otherwise successful
HVAC installation.
All sounds and vibrations are forms of kinetic energy, and in the
HVAC world they are usually derived from moving equipment, moving
air, pressure-reducing equipment, or other moving fluid. A problem
arises when an HVAC system component generates noise or vibration
within, or adjacent to, a habited or process-sensitive space. If the generated sound or vibration level exceeds the local tolerance level, the
HVAC system is deemed unacceptable.
For an HVAC system to be a
SPBRC410 P-HC-BRC41000000 控制器模块 ABB Bailey
