[esp-r] Re: Network Flow Nodes and component connections

[Jon Hand]

Another point of view for flow networks...

During training courses my advise is:

a) imagine you are at the location of the air node
   in the room, look at the component. If above you
   then the delta height is positive. If you look
   down at the component then the delta height is
   negative. Do this for each component except for
   the bi-directional component (door).

b) One approach to networks is to create one boundary
   node for EACH opening/connection to the outside and make the
   height of the boundary node at the centre of the
   opening. When looking from the point-of-view of
   the boundary the delta height is zero.

c) Doors - one of the attributes of a door is the
   distance from the bottom of the door to the 
   adjacent nodes. When using doors in different
   size rooms you will have to make additional
   door components, each with a distance attribute
   that matches the specific room.  When using
   a door the delta heights are zero because the
   component already has the attribute set.

d) There are several exemplar models with flow networks
   look at those to check out these patterns.

-Jon Hand

-----Original Message-----
From: esp-r-bounces at lists.strath.ac.uk on behalf of Paul Strachan
Sent: Sat 10/18/2008 4:39 PM
To: Ryan Joseph Del Balso; 'esp-r at lists.strath.ac.uk'
Subject: [esp-r] Re: Network Flow Nodes and component connections
 
Ryan,

There is a diagram in Jan Hensen's thesis which shows the heights required for the calculations. See page 4.10 in http://www.esru.strath.ac.uk/Documents/PhD/hensen_thesis.pdf

Suppose you have a high level opening between 2 zones and that you specify the connection as a linkage from node X ("positive" node) to node Y ("negative" node). The height of node X is typically placed at the average height of the zone represented by node X, say 2 m above reference; similarly for node Y, say 2.5m above reference.  If the high level opening is at a height of 4m above the reference level, then the "Height of +ve linkage point relative to node X" is +2.0m and the "Height of -ve linkage point relative to node Y" is +1.5m.

If you had a further low level opening between the 2 zones, say at 1.0m above reference, then for this connection, the "Height of +ve linkage point relative to node X" is -1.0m and the "Height of -ve linkage point relative to node Y" is -1.5m.

Regards
Paul

Ryan Joseph Del Balso wrote: 

	Can someone clarify the network flow node height and component connection designations?  The cookbook describes placing the node at the "height" of the opening, but does not define what that height should be.  If I have a door opening, should that height be at the bottom of the opening, the top or the middle?  Also, is the "Height of +ve linkage point relative to node X" supposed to be from the bottom of the component to the node height, or from the node height to the bottom of the component?  Same with the -ve linkage node.  This would affect the sign.  Again, the cookbook and reference literature do not describe this completely or clearly.

	 

	Additionally, the cookbook states that the nodes on either side of the component should be at the same height, but what if you have a single interior node and windows as multiple elevations?  Then only one of those nodes could be at the same height as the internal node?  I am just a little confused on this.

	Thanks

	Ryan