ATLANTA – A consistent approach to the design and application of HVAC for rail passenger vehicles is provided in a newly published guideline from ASHRAE.
“Guideline 23-2016, Guideline for the Design and Application of HVAC Equipment for Rail Passenger Vehicles, was developed in response to a need expressed within the rail passenger vehicle industry to adopt a more consistent approach to the design and application of HVAC systems that can be used as a basis for future designs,” Ken Hesser, chair of the committee that wrote the guideline, said. “Current inconsistent design approaches and sometimes widely varying requirements for similar applications have resulted in minimal standardization, excessive development efforts for similar equipment, and the resulting inefficiency and disproportionately high cost of equipment.”
The guideline applies to passenger carrying rail vehicles. These include three broad categories of rail vehicles or service: urban includes subways, street cars and light rail; commuter (sometimes referred to as regional or suburban) includes primarily electric multiple units (electrically powered from overhead catenary or third rail) and locomotive hauled trains that transport passengers from the suburbs to metro areas; and intercity trains that are typically the locomotive hauled long distance trains.
Estimates on the number of rail passenger vehicles worldwide are in excess of 100,000. Hesser noted that air conditioning design for rail vehicles present unique challenges over designing for buildings. Challenges unique to rail vehicles vs. buildings include:
- Designing equipment to be significantly more mechanically robust to withstand the dynamic shock and vibration environment
- Maintaining comfort with rapidly changing passenger loads and quickly changing environmental conditions (tunnels, stations etc.)
- Maintaining reliable operation in dirty environments
- Ability to continue operation when exposed to extreme transient thermal conditions in tunnels and when positioned adjacent to other heat generating equipment
- High tolerance for rapid supply voltage fluctuation and frequent power interruptions/restarts
- Tight packaging of high capacity equipment in limited spaces.
- Sizing capacity to accommodate rapid cool down/heat up when vehicles are parked without power for extended periods.
The cost of Guideline 23-2016, Guideline for the Design and Application of HVAC Equipment for Rail Passenger Vehicles, is $39, ASHRAE members ($46, non-members). To order, visit www.ashrae.org/bookstore or contact ASHRAE Customer Contact Center at 1-800-527-4723 (United States and Canada) or 404-636-8400 (worldwide) or fax 678-539-2129.
ASHRAE, founded in 1894, is a global society advancing human well-being through sustainable technology for the built environment. The Society and its more than 55,000 members worldwide focus on building systems, energy efficiency, indoor air quality, refrigeration and sustainability. Through research, standards writing, publishing, certification and continuing education, ASHRAE shapes tomorrow’s built environment today. More information can be found at www.ashrae.org/news.