4 FM quick reads on HVAC
1. High-Performance HVAC System Requires an Integrated Design
Today's tip from Building Operating Management comes from Jeffrey Heiken, engineering design principal with Kling Stubbins: A high-performance HVAC system requires an integrated design.
Designing a high-performance HVAC system starts with understanding its end goals. It effectively serves the functional needs of the building and its occupants. It minimizes the use of resources by accurately "right-sizing" components and configurations. It is flexible in response to changes in use. And it employs design elements to capture waste heat, reduce material or energy use, or reuse materials wherever possible.
Across the spectrum of building types, high-performance HVAC systems provide more pleasant and satisfying work environments, and efficiencies which translate into lower owning and operating costs.
But a high-performance HVAC system is impossible without a truly integrated design team fully engaged and focused on project goals from the start. That's because so many aspects of design are interrelated and have to be considered simultaneously to achieve the goal of a high-performance HVAC system. For example, the HVAC design is affected by sustainability elements like daylight projection into the building, which helps drive building footprint and building aspect ratio (length to width dimensions) as well as solar orientation on a site. Daylighting also brings consideration of external shading devices and internal reflective light shelves to prevent glare and heat gain while bringing natural light to the occupied spaces. Internal shading (often mechanized and automated) in concert with computerized lighting control systems are also common energy conservation measures. With all of those factors affecting the HVAC design — not to mention the exterior wall construction, glazing, occupancy and utilization — it's clear that an integrated design approach is essential. From building siting to building envelope composition, the performance of all elements is enhanced.
HVAC can't be an afterthought once the shell of the building has been designed. Compared to the overall building life, the design process is brief and often fast-paced. Attention to HVAC performance at the earliest steps will be felt for decades. So will a lack of attention.
2. When Upgrading Building Automation, Review Capabilities of Existing Systems
Today's tip from Building Operating Management: Before upgrading an existing building automation system, be sure to review the capabilities of the existing automation and HVAC systems.
When facility managers are considering upgrades to existing building automation systems, they are likely to be wowed by the capabilities available. But those capabilities will be useful only if they are implemented.
One of the most important factors to consider when reviewing the capabilities of the new system is that most existing systems are not used to their full potential. Some functions included in the original system may not have been needed when it was first installed. Management may have decided that some functions required too much effort or the collection of too much data to be of value. Still other functions may have been used initially, but dropped due to the lack of sufficient manpower or simply because they were too difficult to use.
Before making a decision to invest in a new system to gain additional system capabilities, make certain that they are not already available with the current system. If they are available, then the facility manager should evaluate whether anything about the new system makes it more likely that those capabilities will be used.
A review of existing capabilities must extend beyond the system itself to the building systems and components they will be interfacing with. Having the ability to control the operation of all building HVAC equipment is a feature needed if managing facility energy use is one of the primary goals of the system. If the HVAC systems themselves do not have the controls of the type and level of sophistication needed, then those HVAC systems will need to be upgraded or the energy savings impact of the new system will not reach its full potential. It may well be worthwhile to upgrade the existing HVAC system, but the option should be carefully evaluated before a decision is made to move ahead with a new building automation system.
3. Waterproofing Strategies for Vegetative Roofs
This is Chris Matt, Managing Editor of Print & E-Media with Maintenance Solutions magazine. Today's tip is waterproofing strategies for vegetative roofs.
Project specifications related to waterproofing of vegetative roofing assemblies should include root barriers and membrane protection, fully adhered or grid-isolated attachment, water testing of the installed membrane, and electronic leak-monitoring systems, if desired.
Fully adhered systems inhibit water movement between the roof deck and the waterproofing membrane, so if a leak occurs, the water will not travel far. This feature simplifies leak detection and repair.
Managers can specify grid isolation if the membrane is loose-laid or partially adhered. When it is adhered in a grid pattern, the assembly isolates leaks to a single area of the grid. For systems that are not fully or grid adhered, locating and repairing leaks can be time-consuming and expensive, particularly on intensive vegetative systems. Specifying an electronic leak-detection system also can reduce costs associated with leaks. If leaks occur, electronic systems can pinpoint the breaches and ensure quick and efficient repairs.
Specifications also should include quality-assurance requirements, including flood testing and regular installation inspections by an independent inspector and a manufacturer's representative.
Many manufacturers require flood testing of waterproofing membranes before the installation of protection mats and growing media. Inspection of the installation, especially of the waterproofing membrane, is essential. Inspectors also should monitor the membrane for damage caused by installers or other workers on site, especially for new construction projects.
Punctures in the waterproofing membrane often can occur after flood testing. If the spaces below the roof are sensitive to moisture, technicians should conduct regular electronic monitoring.
Maintaining vegetative roofs can be relatively simple if managers choose drought-resistant plants and are looking for a natural aesthetic. But some systems require irrigation and regular landscaping.
4. Portable Cooling: Preparation and Planning
This is Chris Matt, Managing Editor of Print & E-Media with Maintenance Solutions magazine. Today's tip is developing a plan for portable cooling.
For managers to realize the full benefits of a temporary cooling system, they must carefully evaluate their buildings' requirements and select the system that most closely meets the needs of their facilities. Planning is the key, but it is difficult, at best, to plan once the cooling service has failed.
The first step in the process is to identify the most critical areas within a facility that would be most adversely affected by the loss of cooling. Not all areas are equally important. Cooling might be necessary to keep computers and other critical electronic equipment operating, or it might provide comfort only. Managers need to determine the impact a loss of cooling services would have on operations.
Next, determine the extent of any potential disruption. Would it be localized in isolated areas within a building, or would it be building-wide? Managers can address localized, temporary cooling requirements through the use of spot, portable systems. More widespread outages might require a building-wide solution.
Another option — one that would not require additional equipment — is to determine if it is possible to temporarily relocate the operations affected by the outage to another location within the facility.
Managers need to evaluate a number of factors before selecting a temporary or portable cooling system. One of the most important steps in this phase is to determine the capacity of the required cooling system. Specify a system that is too small, and the area might not cool properly. Specify one that is too large, and the result will be inefficient operation, frequent cycling of the unit, excessive noise, and improper humidity control.
Managers can develop quick estimates of cooling loads by looking at the power requirements of all equipment operating in the space. They also can ensure more accurate load calculations by having engineers perform the calculations.
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