Although maintaining a competitive procurement process with only one energy-management-system (EMS) vendor may sound impossible, Walt Disney Parks and Resorts' approach to EMS, which standardizes one manufacturer's system, is proof that it is not.
The ability to design, install, program, create graphics for, and continuously improve an EMS in house is important to Disney. With its unique approach to EMS, it has that, along with training, spare-parts, and software-license costs lower than they otherwise would be. There are no surprises, and in the end, everything works.
This article will examine Disney's approach to designing, installing, and operating EMS.
WHAT OWNERS WANT
Building owners desire the same fundamental characteristics in a new EMS:
- Single-seat user interface.
- Compatible with existing EMS.
- Easy to use.
- Easily expandable.
The creation of open protocols has made field-panel interoperability plausible, while the development of overlay systems that communicate with multiple-vendor systems has made single-seat operation possible. However, there is little commonality between different vendors' low-level panel programming, and different service-tool software is needed for each vendor's system, regardless of the open protocol.
In standardizing one manufacturer's EMS, Disney obtains all of the aforementioned desired features. The key to the success of Disney's approach is that its energy-management team is involved throughout design, construction, startup, and ongoing operation.
The following sections will contrast the two methods of designing and specifying an EMS:
- Specify a multivendor interoperable EMS.
- Standardize one manufacturer's EMS.
Specifying a multivendor interoperable EMS is the more common approach. It is as follows:
1) The mechanical engineer completes the HVAC design, including the chiller and boiler plant, pipe and pumping systems, air handlers, ductwork, and temperature controls. The controls design is performance-based and, often, not much more than a set of “typical” schematics accompanied by a narrative specification describing the desired results.
2) To facilitate competitive bidding, several vendors' EMS are identified as acceptable. So that the new EMS will be compatible with existing EMS, the specifications call for EMS panels to communicate via an open protocol.
3) The project is bid and a contract awarded. More often than not, a rough order-of-magnitude estimate based on a percentage of the mechanical contract is used for controls.
4) The mechanical contractor solicits bids from several controls contractors, generally selecting the lowest bidder. The controls contractor's scope is all-inclusive — controllers, sensors, actuators, cable, conduit, etc.
5) The controls contractor prepares a submittal showing the actual EMS design and listing required materials.
6) The mechanical engineer reviews the submittal to determine compliance with the plans and specifications.
7) The EMS is installed by the controls contractor, programmed according to the desired sequence of operation, started, and commissioned.
8) The system is turned over to the owner.
9) The EMS vendor contacts the owner and requests a service contract to maintain the system.
With this approach, even though a new EMS meets specifications, it might not be the same as — or even compatible with — an existing EMS. The new system, then, becomes just another EMS in the owner's portfolio, requiring its own training, spare parts, and software licenses.
The Disney approach to standardizing one manufacturer's EMS requires that EMS hardware be owner-furnished and that EMS designs and specifications be prescriptive in nature. The process is as follows:
1) The mechanical engineer prepares the HVAC design, including the chiller and boiler plant, pipe and pumping systems, air handlers, and ductwork.
2) The mechanical engineer completes a temperature-controls drawing showing control points, the sequence of operation, the location of all EMS panels with 120-v power, and the location of all space-temperature, humidity, and carbon-dioxide sensors. The drawing also includes a controls specification based on the owner's EMS.
3) The electrical engineer completes drawings detailing all motor- and lighting-control schematics, including relays, and showing all underground conduits.
4) The energy-management engineer prepares the EMS design. A drawing that includes a unit-control-panel (UCP) wirelist containing point numbers and sensor types for all input/output cables is pre-pared, as is an EMS communication block diagram with UCP-enclosure mounting details.
5) The energy-management engineer prepares a specification describing the work to be completed inside of the EMS panels.
6) The project is bid and a contract awarded.
7) The owner furnishes all of the EMS modules, EMS panels, and components used inside of the UCP.
8) The mechanical contractor competitively bids the “outside-the-UCP” work, which includes the wires, conduits, sensors, and actuators detailed in the EMS design drawing and specification. A controls contractor is hired.
9) The controls contractor prepares a submittal containing equipment details for the job. This could be something as simple as a set of material cut sheets or something as comparatively complex as control diagrams for each piece of equipment, with point numbers and cable information from the EMS design drawing.
10) The mechanical engineer reviews the submittal to determine compliance with plans and specifications.
11) The controls contractor installs, labels, and terminates all of the field devices and pulls cables back to the EMS panels, leaving 10 ft of slack for final termination by the owner or EMS contractor.
12) The controls contractor completes a cable/device checklist to verify proper installation and labeling. A signed copy is submitted to the owner as notification for the EMS contractor to begin.
13) The owner or an EMS contractor familiar with the owner's EMS is hired to perform the “inside-the-UCP” work, including wire termination, programming, and startup.
14) The temperature-controls and EMS contractors work together to commission the EMS and verify the operation of each control point.
15) After building acceptance, the EMS is turned over to the owner.
16) The owner coordinates the connection of the EMS to the corporate Ethernet network and uploads all EMS panels to the central EMS server.
17) The owner prepares the EMS graphics and fine-tunes time and set-point schedules.
With this EMS-design approach, the owner knows exactly what it is getting and knows that the integration of its new EMS into its existing one will be seamless.
Competitive bidding is used to select the controls contractor, which comprises the largest portion of the EMS-installation cost. Because it is included in the design documents, with each input/output-point number given, the installation of all of the wires, conduits, sensors, and actuators also may be bid competitively.
The owner negotiates with the preferred EMS vendor on unit pricing for the EMS control modules.
Walt Disney Parks and Resorts' EMS-design approach is both simple and straightforward. Disney's EMS design expertise comes from day-to-day EMS operational experience and from the development of EMS design standards. Disney keeps its focus on the end result — an EMS that minimizes facility energy use, is easy to use, and is flexible enough to meet changing facility needs.
ABOUT THE AUTHORS
The chief energy-management engineer for Reedy Creek Energy Services, a division of the Walt Disney World Co., Paul J. Allen, PE, is responsible for the development and implementation of energy-conservation projects throughout Walt Disney World Resort. He has bachelor's degrees in physics and civil engineering from the University of Miami and master's degrees in civil engineering and industrial engineering from the University of Florida. In 2003, he was inducted into the Association of Energy Engineers Hall of Fame. He can be contacted at [email protected].
The principal engineer of EMS for Reedy Creek Energy Services, Christopher D. Sandberg designs EMS for Walt Disney Parks and Resorts facilities around the world. He has a bachelor's degree in construction engineering and management from Purdue University and a master's degree in building construction from the University of Florida. He can be contacted at [email protected].