Case Study: Cuyahoga Metro Housing Authority Utilizes BAS

BAS Concepts

一个BAS的目标是让建筑设备，以更有效地和自动操作，基于外部因素。大多数情况下，这意味着建立反映当天，室外温度，或客户需要的时间设备操作。Heating and cooling systems, lighting, security, and fire alarm systems are common building components that usually benefit from automation. In years past, these systems might have consistently been placed in either “on” or “off” mode, and where building system efficiencies could be pursued, manual adjustments based on years of assumed best practices were considered, but not often consistently.

In today’s facilities management realm, BASs are increasingly common because of the clear advantages offered by automation. In addition to energy savings, these systems reduce the amount of maintenance staff time and therefore also reduce overhead costs. An upgrade from a manually operated mechanical/electrical equipment plant to a BAS at a minimum must include new sensors, new controllable equipment devices (valves, on/off switches, etc.), and a control station (computer) with software specifically designed to monitor and automatically adjust building equipment operations.

Basic Scope of the CMHA BAS

In CMHA’s case,33场建设用地（下载包括CMHA建筑工地上的列表并在每个自动化楼宇设备）是自动不同程度。CMHA的努力目前集中在他们的建筑机械系统。他们已经自动化了热水发电系统建设采暖和生活用以及冷冻水系统，提供空调。一个CMHA建筑群，望湖大厦，并还对安全和火灾报警BAS联系。该CMHA系统完全在未来可扩充为更大的楼宇设备自动化，如鼓风机，ductworkdampers, more chillers, and interior lighting, just to name a few.

This BAS installation was a $1 million element of a larger $33 million能源执行ance contractthat provided more efficient boilers and chillers and building envelope enhancements including new roofs, windows, and doors. The BAS portion of the overall project came with a utility cost-savings guarantee of over $175,000 annually. CMHA’s BAS operations have substantially exceeded the predicted utility savings during the past two years.

系统操作参数是关键

BAS operating parameters are changeable, but an initial round of sensor and system settings was loaded into the CMHA software during installation. These trial parameters, based on installed equipment specifications and known best practices, were later tested and adjusted to optimize building system performance. For example, outside temperatures during the winter will trigger the heating water circuits in each building to operate at optimum temperatures. A winter day with a high of 40 degrees Fahrenheit might demand a heating water circuit temperature of 145 degrees at a specific site. A 10 degree day might require a heating water circuit temperature of 175 degrees. The BAS will sense outside temperature fluctuations and efficiently command the boilers and pumps to provide the temperature and volume of heating water required to keep the residents comfortable. The BAS-controlled chilled water systems provide building air-conditioning in a similar manner during the summer months.

In CMHA’s case, BAS operations are aided by the understanding that residential heating and cooling demands are relatively static, particularly in buildings where thermostat settings are established by written policy. In other venues outside CMHA, non-residential building functions such as manufacturing processes and office environments are more dynamic in terms of heating and cooling demands. However, even these more complicated building occupancies still readily accommodate BAS technologies and their operating software.

Remote Monitoring

CMHA建筑系统是由得克萨斯州达拉斯市西门子楼宇科技公司的中央控制中心连续监测，通过互联网连接。CMHA的维修人员和他们的主管通过电子邮件时建立系统的运行性能，从偏离协议的通知。任何符合条件的楼宇设备偏差触发系统警报，电子邮件启动到合适的员工CMHA。最明显的电子邮件通知的例子是响应了一块机械设备突然无法正常使用。否则可操作的建筑系统内不期望的温度偏差会触发电子邮件通知的那么严重，但同样重要的例子。

因为他们有一个内部的维修人员，可以建立突发事件每天24小时响应的电子邮件通知的安排是适当的CMHA。其他建筑物的业主可能会受益于更强大的BAS供应商协议。不仅通知，而且设备运行和调整，可以通过远程控制中心从建筑工地进行，潜在千里。

Total System Awareness

指定CMHA的工作人员可以在任何时候通过BAS软件来远程登录的能力。该方案的主要页面显示为每CMHA大楼网络中的总结设备状态。无论从西门子达拉斯控制中心收到任何电子邮件通知，任命CMHA人员必须打开或关闭建筑设备或调整设备运行参数的能力。该BAS软件记录的活动，从而发起的任何设备调整日期和时间，是谁发起行动的职员。通过在设备级维修人员发起的任何系统的活动同样可以识别和监控。The images to the right are actual screen shots of the CMHA system. They are building specific and show various equipment operating modes and alarms, as would be seen by a BAS-system user.

其他优点的BAS CMHA管理人员are the oversight and reporting capabilities it offers. Technical questions about equipment histories can be readily answered. Reports describing various equipment operations over time can be printed from the system. Just about any data regarding the equipment operated by the BAS can be captured and printed out as a report.

Preview of Operational Savings

虽然我们将进入更详细的在以后的文章，这里的经营节约BAS可以提供​​一个简单的例子。“操作”储蓄通常超出在BAS合同往往形式化的节能协议。假设，安装BAS之前，在CMHA建设服务于国内热水箱中的一个锅炉意外关闭。由于他们的坦克之一可能拥有的热水500加仑客户投诉可能不会触发小时维修响应，罐后要成为耗尽的热水或冷却下来。

However, with the BAS in place, in this same scenario a notification would be issued immediately. This allows for a maintenance team response before any building resident realizes that there’s a concern. Avoiding the need for maintenance crews to record and respond to dozens of residents’ trouble calls offers significant savings. This is only one simple example of overhead savings in staff time, not to mention the improved customer service aspects, which are also important and cannot be assigned a specific dollar value. Join us next time and we’ll discuss more details of CMHA’s BAS.

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Mr. Michael Hughes was a technical contributor to this feature. He is Chief of the Construction Department for theCuyahoga Metropolitan Housing Authority(CMHA).

Mr. William Davis was a technical contributor to this feature. He is a Senior Account Executive with the Building Technologies Division of西门子工业公司.