[BLDG-SIM] Energy use for elevators

[Leonard Sciarra]

although, for a truly sustainable building, not all elevators are
created equal, and one should look for those manufacturers that are
making more efficient motors


quick link, 


http://www.aceee.org/buildings/coml_equp/elevators.pdf

http://www.energyideas.org/default.cfm?o=h,g,ds&c=z,z,1709
 

Question:


What is the relative energy efficiency of various elevator drive
mechanisms? For example, some elevators use "regenerative" motors (when
the carriage goes down, the motor acts as a generator and pumps current
back into the electrical network, producing energy savings). 


Answer:


The following describes various types of elevators.  

Low-rise buildings may use an elevator driven and supported by a
telescoping jack powered by a hydraulic motor. These units operate at a
low, fixed-speed, do not feature regenerative braking, and have a
limited travel or lift of approximately 25-feet. 

For a building with seven or fewer floors, a variation of the hydraulic
elevator may be specified that features a constant speed hydraulic pump
which imparts pressurized hydraulic fluid onto a hydraulic elevator
drive motor. Varying the control valve setting provides the ability to
vary the elevator speed. These hydraulic elevators are equipped with
counterbalances, but do not have regenerative braking. These units are
often found in mid-rise facilities with "residential" usage
characteristics, such as apartments, condominiums, or nursing homes.

High-rise buildings are served by geared or gearless traction elevators.
These elevators are driven by DC MG sets, silicon controlled rectified
(SCR) DC motors, or variable voltage variable frequency (VVVF) drives
coupled to AC motors. All of these configurations provide variable and
high-speed operation and provide regeneration, but exhibit different
operating efficiencies. 

Dover Elevators has calculated the average kWh required per day for a
single elevator equipped with MG, SCR, and VVVF drives (see table
below). Elevators with hydraulic drives would be expected to use about
25% more energy than the SCR drive. The average energy use values are
given for elevators of various capacities, serving from 3 to 32 floors,
and are based upon an 8-hour operating day and an elevator with a
maximum full-load mass of 19,000 pounds. 

Average Energy Consumption (kWh) Per Day

	
Number of 

Floors

	2500 # Capacity

	4000# Capacity

	
VVVF

	SCR 

	MG

	VVVF

	SCR

	MG

	
5

	31

	53

	72

	49

	84

	115

	
10

	39

	54

	76

	62

	86

	121

	
20

	48

	57

	94

	76

	92

	151

	
30

	58

	67

	102

	92

	108

	164

	

Note: Average energy consumption values are based on 8 hours of elevator
operation per day. If energy consumption for 10-hour operation is
desired, multiply the numbers in the table by 1.25 

In general, traction elevators, or elevators with regeneration
capability, initially cost twice as much as hydraulic units, and are
typically found in office buildings with heights of 5 stories or
greater. 

 	 56732  1709	
 

Leonard Sciarra, AIA, LEED ap

312.577.6580 (Dir)

G E N S L E R | Architecture & Design Worldwide

30 West Monroe Street

Chicago IL, 60603

312.456.0123

leonard_sciarra at gensler.com 

 

________________________________

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Vikram
Sami
Sent: Thursday, July 26, 2007 4:30 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Energy use for elevators


It does because it makes the percentage energy saved smaller. 
 

Vikram Sami, LEED AP 
Direct Phone 404-253-1466 | Direct Fax 404-253-1366 

LORD, AECK & SARGENT ARCHITECTURE
1201 Peachtree Street NE, Suite 300, Atlanta, GA 30361 
Responsive Design * Technological Expertise * Exceptional Service 
www.lordaecksargent.com 

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________________________________

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Graham
Carter & Megan Lyall
Sent: Thursday, July 26, 2007 4:52 PM
To: BLDG-SIM at gard.com
Cc: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Energy use for elevators


Does it really matter that this end use is included if the Base Case
vertical transportation energy use is the same as the Design Case? 

On 25/07/2007, at 11:06 PM, Eric Yang wrote:


		It is from Table G-1 of the "User's Manual of ASHRAE
90.1 2004".   The schedule has a different percentage for each business
hour. I believe there have been several discussions on this topic, and
you can search in this mailing list.  Drury Crawley previously
recommended a white paper from ACEEE about the actual energy
consumptions of elevator usage.
http://www.aceee.org/buildings/coml_equp/elevators.pdf
<http://www.aceee.org/buildings/coml_equp/elevators.pdf>    If you use
Energyplus, the schedule is already combined in its standard schedule
library.

	Hope this helps.

	Eric

	________________________________

		From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On
Behalf Of Zhen Tian
	Sent: Tuesday, July 24, 2007 10:56 PM
	To: BLDG-SIM at gard.com
	Cc: BLDG-SIM at gard.com
	Subject: [BLDG-SIM] Energy use for elevators

		Eric,

		Thanks a lot for your reply.

		I have a further question. If we have the elevator power
data, what appropriate schedule should we use to approximately to get
the elevator annual energy use?

		I checked the ASHREAE Appendix G but cannot find
appropriate schedule for elevators.

	I think the schedule of elevators are quite diffent from other
schedules like occupancy scheule. One example, supposing people work
from 8am to 6pm continuously, I guess that elevator working schedule
should not be the same. Do you have any ideas what appropriate schedule
should we use?

		Thanks a lot.

		Regards,

		David 
	
	Eric Yang <Eric.Yang at smithgroup.com> wrote:

		Yes, ASHRAE 90.1 Appendix G requires modeling elevator
energy as long as it is designed in the project. You can come up a
realistic schedule or stick to a standard schedule in Appendix G if
necessary. 
		
		Eric
		Smithgroup
		
		
		-----Original Message-----
		From: BLDG-SIM at gard.com on behalf of Zhen Tian
		Sent: Mon 7/23/2007 10:36 PM
		To: BLDG-SIM at gard.com
		Subject: [BLDG-SIM] Energy use for elevators
		
		Dear All,
		
		I have seen some messages these days asking the energy
use of elevators. But it seems that there is no very accurate way of
modeling annual lift energy use.
		
		If we need to simulate building energy use according to
ASHRAE 90.1-2004 for LEED accrediation in e-QUEST, do we need to
simulate elevator energy use or not? Is it a must do? Could somebody
with experience with this topic give me some hints?
		
		Thanks a lot in advance.
		
		Regards,
		
		David
		
		
		
		
		
		
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