[Bldg-sim] District Thermal Energy

[Neeraj Arora]

Hi Friends,

 

 

I am doing a District thermal energy model (referring DTE in LEED NC ver 2.2
and LEED for schools ver 1.0, May 28, 2008). 

 

It includes step-1 (proposed and baseline) and step-2 (proposed and
baseline) eQuest models.

 

There is no space heating in the actual design.

 

The HVAC system types are as per the following:

 

*	Step-1:

*	Proposed Case: Chilled water meter, AHU as single zone reheat with
electric heat pump as heat source (But there is no space heating in the
actual design) and zone heat source not installed. And FCUs modeled as FCUs
with with electric heat pump as heat source (But there is no space heating
in the actual design) and zone heat source not installed.

 

*	Baseline Case: Chilled water meter, AHU as single zone reheat with
electric heat pump as heat source (But there is no space heating in the
actual design) and zone heat source not installed. And FCUs modeled as FCUs
with electric heat pump as heat source (But there is no space heating in the
actual design) and zone heat source not installed.

 

*	Step-2:

*	Proposed Case: Complete on site Chiller plant with cooling tower and
primary secondary pumping, AHU as single zone reheat with electric heat pump
as heat source (But there is no space heating in the actual design) and zone
heat source not installed. And FCUs modeled as FCUs with electric heat pump
as heat source (But there is no space heating in the actual design) and zone
heat source not installed.

 

*	Baseline Case: AHU as packaged single zone and FCU as PTAC as per
the document District Thermal Energy in LEED NC ver 2.2 and LEED for schools
ver 1.0, May 28, 2008. Heating by electric heat pump. We have also modeled
PTAC cooling EIR and heating EIR as per ASHRAE 90.1-2004

 

Step-1 Baseline: 

*	Total heating load  (SS-D command) = -64.29 MBTU
*	Total heating energy consumption (from the output) = 18.8 * 10^3 kWh

 

Step-2 Baseline: 

*	Total heating load  (SS-D command) = -94.747 MBTU
*	Total heating energy consumption (from the output) = 49.5 * 10^3 kWh

 

The issue is:

 

Q-1: Why the heating loads in the step-1 and step-2 are not consistent?
(Where as in the step-1 and step-2 proposed cases the heating loads hence
the energy consumptions are consistent)

 

Please note that all other parameters are same in both step-1 and step-2
baseline models.

 

 

Regards,

 

 

Neeraj Arora

Project Engineer

Kamal Cogent Energy Pvt Ltd. 

1st floor, Kamal Ratan Chambers,

M.I.Road, Opp GPO

Jaipur-302001, Rajasthan (India)

Ph - 0091-141-2373184 / 85

 

 

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