Ransen's Lighting Energy Numeric Indicator (LENI) Blog: LENI

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Tuesday, March 8, 2022

Roof lights in the LENICALC XML format

Roof lights can only be placed on the top floor of a building and are always aligned with the x or y axes of the world. Here is an example of two roof lights and their daylight areas:

In the XML the roof light in lower left looks like this:

Note that LumList is an empty branch, which means no luminaires are controlled by the light from this rooflight

Monday, March 29, 2021

LENI XML files which contain results of calculations

In this article I described the structure and details of a LENI XML file. It is possible to have a LENI XML file with actual calculation results embedded in them. There are results for the building, its floors and its rooms.

Here is a typical result branch:

If this branch is at the top level of the XML file then this is the result of a calculation of a whole building, the LENI.

If it is inside a Floor branch then it is the LENIsub of that floor. And if it is inside a room branch it is a LENIsub of that room.

So <LENIResult> is a number which is either a LENI value or a LENIsub value. LENI always applies to a whole building. <LENIsub> applies to an individual floor or an individual room.

Note also that <InstalledPower> is not strictly directly used in the calculation, but is nice to have as extra information.

Here is an actual LENI project file with calculation results at all three levels (building, floor and room):

Tuesday, February 2, 2021

Text values for fields in the LENICALC program and LENI XML files

Here are the strings that can appear in given "non numeric" or "type" fields in a LENIXML project file.

Control technique

Control techniques are part of a zone. Example:

Allowed types:

"Manual",
"Automatic Switched On/Off",
"Automatic Switched On/Off In Stages",
"Automatic Daylight Responsive Off",
"Automatic Dimmed Stand-by Losses Switch On",
"Automatic Dimmed No Stand-by Losses Switch On",
"Automatic Dimmed Stand-by Losses No Switch On",
"Automatic Dimmed No Stand-by Losses No Switch On",

Shading of a room

Example:

<Shading type="No Shading" />

Allowed types:

"No Shading",
"Glare Protection",
"Auto Glare Protection",
"Light Guides",

Product type flags.

Example, inside a product in the Products list:

<Products>
    <LumTypeData refid="5678">
        <TypeFlags>4</TypeFlags>

A product can have any combination of these three things
m_ikLuminaireFlag = 1;
m_ikControlFlag = 2;
m_ikEmergencyFlag = 4;

{L"Luminaire",                   CLumTypeData::m_ikLuminaireFlag},
{L"Control",                     CLumTypeData::m_ikControlFlag},
{L"Emergency",                   CLumTypeData::m_ikEmergencyFlag},
{L"Luminaire+Emergency",         CLumTypeData::m_ikLuminaireFlag | CLumTypeData::m_ikEmergencyFlag},
{L"Luminaire+Control",           CLumTypeData::m_ikLuminaireFlag | CLumTypeData::m_ikControlFlag},
{L"Control+Emergency",           CLumTypeData::m_ikControlFlag   | CLumTypeData::m_ikEmergencyFlag},
{L"Luminaire+Control+Emergency", CLumTypeData::m_ikLuminaireFlag | CLumTypeData::m_ikControlFlag | CLumTypeData::m_ikEmergencyFlag},

See also TypeFlags in the section below for another example.

Product control system

The product control system is an integer inside the luminaire/product branch.

    <LumTypeData refid="123ABC">
        <Desc>ACME LUX 123ABC description</Desc>
        <TypeFlags>1</TypeFlags>
        <ProdConSys>1</ProdConSys>
        <MaxPow>100.0000000</MaxPow>
        <StandbyPow>0.0100000</StandbyPow>
        <ChargePow>0.0100000</ChargePow>
    </LumTypeData>

It will have a value from 0 to 2:

"Daylight", 0,
"Occupancy", 1,
"Constant Illuminance Sensor", 2

Occupancy control system (ocs) of a zone

Example:

ocs can be set to one of the following integer values:

"1. Manual On/Off Switch",
"2. Manual On/Off switch + additional automatic sweeping extinction signal, and Auto on/Dimmed",
"3. Auto on/Auto off and Manual on/ Dimmed",
"4. Manual on/Auto Off"),

Choices of lux in a zone

Example (the zone list is the list of zones in a room):

Allowed values for zonelux are:

{ 20.0, 30.0, 50.0, 75.0, 100.0, 150.0, 200.0, 300.0, 500.0, 750.0, 1000.0, 1500.0, 2000.0, 5000.0 };

Rooflight orientation strings and ids

In the XML the orientation is an integer corresponding to one of these strings:

"Horizontal", CLENIRoofLight::ekRLHorizontal,
"South", CLENIRoofLight::ekRLSouth,
"South East/West", CLENIRoofLight::ekRLSouthEastWest,
"East West", CLENIRoofLight::ekRLEastWest,
"North East/West", CLENIRoofLight::ekRLNorthEastWest,
"North", CLENIRoofLight::ekRLNorth

ekRLHorizontal = 0,
ekRLSouth = 1,
ekRLSouthEastWest = 2,
ekRLEastWest=3,
ekRLNorthEastWest=4,
ekRLNorth=5,

For an example see orient= "4" in the following section

Roof light types

Example (a roof light is inside the roof light list of a room)

Allowed values:

"ShedRoofLight",
"FlatRoofLight",

Building types, and room types and absence factors.

Each building type has its list of room types. Every LENI1XML project has a single building type, for example

<DominantBuildingType>Educational buildings</DominantBuildingType>

The rooms in the building are not restricted to what occurs in any particular building type.

<BuildingType type="Residential buildings" fa="0.00" td="1820" tn="1680">
    <RoomType type="Living room" fa="0.30"/>
    <RoomType type="Bedroom" fa="0.40"/>
    <RoomType type="Room for children or retired persons" fa="0.30"/>
    <RoomType type="Dining room" fa="0.70"/>
    <RoomType type="Kitchen" fa="0.60"/>
    <RoomType type="Bathroom" fa="0.80"/>
    <RoomType type="Toilet" fa="0.90"/>
    <RoomType type="Entrance hall" fa="0.80"/>
    <RoomType type="Corridor, stairs" fa="0.70"/>
    <RoomType type="Storeroom" fa="0.90"/>
    <RoomType type="Cellar" fa="0.95"/>
    <RoomType type="Laundry" fa="0.98"/>
    <RoomType type="Larder" fa="0.98"/>
    <RoomType type="Workroom" fa="0.60"/>
    <RoomType type="Home workshop" fa="0.80"/>
    <RoomType type="Garage" fa="0.95"/>
</BuildingType>
<BuildingType type="Offices" fa="0.20" td="2250" tn="250">
    <RoomType type="Cellular office 1 person." fa="0.40"/>
    <RoomType type="Cellular office 2-6 persons." fa="0.30"/>
    <RoomType type="Open plan office > 6 persons sensing/30m2" fa="0.00"/>
    <RoomType type="Open plan office > 6 persons sensing/10m2" fa="0.20"/>
    <RoomType type="Corridor (dimmed)" fa="0.40"/>
    <RoomType type="Entrance hall" fa="0.00"/>
    <RoomType type="Showroom/Expo" fa="0.60"/>
    <RoomType type="Bathroom" fa="0.90"/>
    <RoomType type="Rest room" fa="0.50"/>
    <RoomType type="Storage room/Cloakroom" fa="0.90"/>
    <RoomType type="Technical plant room" fa="0.98"/>
    <RoomType type="Copying/Server room" fa="0.50"/>
    <RoomType type="Conference room" fa="0.50"/>
    <RoomType type="Archives" fa="0.98"/>
</BuildingType>
<BuildingType type="Educational buildings" fa="0.20" td="1800" tn="200">
    <RoomType type="Classroom" fa="0.25"/>
    <RoomType type="Room for group activities" fa="0.30"/>
    <RoomType type="Corridor (dimmed)" fa="0.60"/>
    <RoomType type="Junior common room" fa="0.50"/>
    <RoomType type="Lecture hall" fa="0.40"/>
    <RoomType type="Staff room" fa="0.40"/>
    <RoomType type="Gymnasium/Sports hall" fa="0.30"/>
    <RoomType type="Dining hall" fa="0.20"/>
    <RoomType type="Teachers' staff common room" fa="0.40"/>
    <RoomType type="Copying/storage room" fa="0.40"/>
    <RoomType type="Kitchen" fa="0.20"/>
    <RoomType type="Library" fa="0.40"/>
</BuildingType>
<BuildingType type="Hospitals" fa="0.00" td="3000" tn="2000">
    <RoomType type="Wards/Bedroom" fa="0.00"/>
    <RoomType type="Examination/Treatment" fa="0.40"/>
    <RoomType type="Pre-Operation" fa="0.40"/>
    <RoomType type="Recovery ward" fa="0.00"/>
    <RoomType type="Operating theatre" fa="0.00"/>
    <RoomType type="Corridors" fa="0.00"/>
    <RoomType type="Culvert/conduct/(dimmed)" fa="0.70"/>
    <RoomType type="Waiting area" fa="0.00"/>
    <RoomType type="Entrance hall" fa="0.00"/>
    <RoomType type="Day room" fa="0.20"/>
    <RoomType type="Laboratory" fa="0.20"/>
</BuildingType>
<BuildingType type="Manufacturing factory" fa="0.00" td="2500" tn="1500">
    <RoomType type="Assembly hall" fa="0.00"/>
    <RoomType type="Smaller assembly room" fa="0.20"/>
    <RoomType type="Storage rack area" fa="0.40"/>
    <RoomType type="Open storage area" fa="0.20"/>
    <RoomType type="Painting room" fa="0.20"/>
</BuildingType>
<BuildingType type="Hotels" fa="0.00" td="3000" tn="2000">
    <RoomType type="Entrance hall/Lobby" fa="0.00"/>
    <RoomType type="Corridor (dimmed)" fa="0.40"/>
    <RoomType type="Hotel room" fa="0.60"/>
    <RoomType type="Dining hall/cafeteria" fa="0.00"/>
    <RoomType type="Kitchen" fa="0.00"/>
    <RoomType type="Conference room" fa="0.40"/>
    <RoomType type="Kitchen/storage" fa="0.50"/>
</BuildingType>
<BuildingType type="Restaurants" fa="0.00" td="1250" tn="1250">
    <RoomType type="Entrance hall/Lobby" fa="0.00"/>
    <RoomType type="Corridor (dimmed)" fa="0.40"/>
    <RoomType type="Hotel room" fa="0.60"/>
    <RoomType type="Dining hall/cafeteria" fa="0.00"/>
    <RoomType type="Kitchen" fa="0.00"/>
    <RoomType type="Conference room" fa="0.40"/>
    <RoomType type="Kitchen/storage" fa="0.50"/>
</BuildingType>
<BuildingType type="Wholesale and retail service" fa="0.00" td="3000" tn="2000">
    <RoomType type="Sales area" fa="0.00"/>
    <RoomType type="Store room" fa="0.20"/>
    <RoomType type="Store room, cold stores" fa="0.60"/>
</BuildingType>
<BuildingType type="Other" fa="0.00" td="1000" tn="1000">
    <RoomType type="Waiting areas" fa="0.00"/>
    <RoomType type="Stairs (dimmed)" fa="0.00"/>
    <RoomType type="Theatrical stage and auditorium" fa="0.00"/>
    <RoomType type="Congress hall/Exhibition hall" fa="0.00"/>
    <RoomType type="museum/ Exhibition hall" fa="0.00"/>
    <RoomType type="Library/Reading area" fa="0.00"/>
    <RoomType type="Library /Archive" fa="0.00"/>
    <RoomType type="Sports hall" fa="0.00"/>
    <RoomType type="Car parks office - Private" fa="0.00"/>
    <RoomType type="Car parks - Public" fa="0.00"/>
</BuildingType>

Atrium type

Example:

Allowed types:
"courtyard",
"atrium",

Wall and Window IDs in the LENICALC program and LENIXML files

A room is simply a polygon. The first wall of the room is the line from the first coordinate in the polygon to the second coordinate in the polygon, and so on. The first wall has id "0", the second wall id "1", and so on.

Windows belong to rooms, in fact windows belong to walls in a room. The window's id is formed by the wall id and the window id. The window id is simply an integer starting at "0" for the first window added to that wall. The second window added to the wall will have id "1", and so on. The window id does not define a geometrical order, only the historical order of when the window was added to the room.

Here is an example:

So the window XML says which wall it belongs to, as well as its height and width, and also how far along the wall it is. The x position of the window is measured from the start of the wall on the right when looking at the wall from inside the room:

The y position is the distance from the floor to the bottom of the window. 1 meter in the above example.

Monday, September 21, 2020

LENI Control Systems vs LENI Control Techniques

LENI is so complicated it can be easy to confuse control systems with control techniques.

Control Systems (in LENI terminology) are illustrated by this graph:

There are four of them and they are to do with how (intelligent sensor controlled) lighting reacts to the presence and absence of (forgetful) people.

Fo, occupancy, is a measure of whether the room is occupied or not in a given time period.

Fo = 1 if the lights are controlled centrally and the controller (human or automatic) does not know or care whether the rooms are occupied or not.

Fo < 1 if the room lights are switched on and off according to whether the room is in use or not. Again it could be a manual human control system (on off switch) or an automatic presence detecting system.

You'd think that...

Fa = 1 - Fo

...and that is true for Manual On/Auto Off, but not for any of the other three. I can only imagine that the curve for Manual On/Auto Off is the best one. A person enters the room, switches on the light, and even if s/he is forgetful, the automatic system will switch off the lights when the person leaves.

The manual on/off switch presumably takes into account the fact that lights can be left on by mistake when a persons leaves and the room becomes empty.

Here's my own personal idea about the graph:

So that was the Control Systems (Occupancy Control Systems would be a better name).

Then there are Control Techniques, there are eight of them, and specify how (intelligent sensor controlled) lighting reacts to the daylight supply of the room. To give them their full name they are Daylight-Responsive Control Techniques. They are summarized in this table:

This table needs some explanation. It is a look-up table, given three parameters you can lookup the output. The output is Fdc, used to calculate the Daylight Dependency Factor.

The first input is type of control, which is basically the first four columns in the above table. There are eight of them (from I to VIII).

The second input is daylight availability, as a simple choice between three options, Low Medium and Strong.

The third input is lux required, maintained illuminance, as an option between 300lx, 500lx and 750lx.

Summarizing:

...and the output from the table lookup is used in the formula for Fd...

AD and non AD areas in a LENI calculation

Since I've fallen into this trap myself I thought I'd warn you others out there about the difference between AD and AND zones in a LENI calculation.

In a zone an AD area is an Area illuminated by Daylight. In other words the horizontal rectangle attached to the vertical window which models the area illuminated by light coming through the window from outside.

So here is a simple room with two windows and their AD rectangles in pink:

The size of the rectangles (based on the size of the window generating the area) is explained in the EN 15193-1 standard itself.

The AND (Area No Daylight) is everything in the room which is not in a window's AD area, so the dark green shown below:

The trap that I sometimes fall into is I put lighting products which respond to daylight in areas which do not receive daylight!

Here's the same room in plan view, with lighting products in AD and AND areas:

The image above illustrates how the LENI standard evaluates the energy consumption of luminaires based not only on their intrinsic consumption, but also whether they are placed in an area affected by daylight or not.

Note that putting any luminaire in a window zone will, according to the standard, reduce its consumption somewhat.

Monday, January 27, 2020

LENICALC Windows program for the EN 15193-1 standard

LENICALC is a program which does all the EN-15193-1 calculations for you, as long as you have all the right data of course. Click on the LENICALC icon on the download page:

Download LENICALC

It is free and runs on any 64 bit Windows operating system from Windows 7 and upwards.

I strongly advise that you read and do the two tutorials in this online help file before you start creating your own LeniCalc project.

Note when you install the program you'll get the Windows help file with the same tutorials, but it may be that the online version gets updated more often.

Monday, December 30, 2019

LENI Pn x Fc and Fcc constant illuminance control.

Let's look at that formula again:

Fc is the constant illuminance (dependency?) factor, and relates to how light output from a given luminaire decays over time and how constant illuminance controls can compensate for this.

If there is not constant illuminance control then Fc is 1. If there is constant illuminance control... then the situation gets more complicated.

You now need to know about:

Fcc, the efficiency of the constant illuminance control
Constant Lumen Output, CLO, which adjust power (over time) in the luminaire to keep the output (in lumen) constant as the luminaire degrades.

Here is how I have explained this part of the EN 15193-1 it to myself:

The top left quadrant of diagram above uses Fcc. Fcc is/was bit of a mystery to me and only by asking my Italian colleagues could I begin to understand it.

From the actual EN 15193-1 standard:

"Fcc = Factor for the efficiency of the constant illuminance control"

The Interweb was no help, so here is my explanation, interpretation, guess.

Efficiency in what sense? It seems that it means efficiency in how it handles the constant illuminance control, i.e. how accurate it is in keeping the flux and illuminance at the required level in various conditions.

In other words a low Fcc system would not change the flux appropriately, and a high Fcc system would change the flux appropriately.

So a better definition, if I have it right, would be:

"Fcc = Factor for the accuracy of the constant illuminance control"

I'm willing to be corrected by anyone who can point me to a complete explanation of Fcc.

Luigi Schiavon gave me this explanation:

When we say Fcc = 1, it means that a reduction of 50% of the power to the luminaire would result in a reduction of 50% of the flux of the luminaire. Probably, in reality, it could be that a reduction to 50% of the full flux requires 70% of the power, and Fcc would be calculated at 0.5/0.7 in this example, and so Fcc= 0.714.

It is also very possible that the relationship between flux and power is not linear, so a single number, Fcc, cannot characterize it.

In practice, with all the approximations already used inside the LENI calculation, we can take Fcc=1, because Fcc does not influence the final result very much. Plus obtaining a real value for Fcc for luminaires probably requires heroism above and beyond the call of duty.

And here's a post on how to use AD and AND areas.

And here's a link to a program which calculates LENI for you.

Monday, December 23, 2019

Overview of the LENI EN 15193-1 formulas.

Lets look a bit more into the top level formulas of LENI...

...and this is part of the numerator of the LENI formula...

...but what do all those terms mean?

The simplest term is Pn, the total installed power for lighting, ignoring emergency lighting and charging of emergency lighting batteries. The n stands for "normal" I presume, as opposed to "emergency" or "charging".

Fc (more on this here) can reduce the weight of Pn because constant illuminance control (CIC) can reduce the power used to illuminate the room. This can happen because sunlight enters the room and electronic controllers react to it and reduce the power driving the luminaires.

Fo is the occupancy factor and takes into account that often lights are switched off when rooms are not occupied. For example a store cupboard may have 50W of lighting installed, but it is only ever switched on when someone goes into it to get a broom. Say 0.1 or 10% of the time. This would make the actual consumption be calculated at 5W (not 50W).

The terms in square brackets are a way of splitting the calculation into day-time and night-time periods.

td is day-time hours. tn is night-time hours.

td x Fd: is a term which can be thought of as: "how much lighting will I need during the day":

Fd is 0.0 if there is always enough natural light during the daylight hours.
Fd is 1.0 if artificial lighting is always required during daylight hours, for example in a room with no windows, no natural light.
Fd is somewhere between 0 and 1 if, during the day, you sometimes need to switch a light on, but not always.

tn does not have a factor because you know you need lighting at night-time. And if nobody goes into the room at night-time is handled by Fo, the occupancy factor.

So...

Fo[(td x Fd) + tn]

...handles the energy consumption change because occupancy of the room, requirement for lighting energy during the day and requirement for lighting energy during the night.

The next entry is on constant illuminance control.

Friday, December 6, 2019

What is LENI? (Lighting Energy Numeric Indicator)

LENI (European Standard EN 15193-1) is a way of giving a number to the energy consumption for lighting in a building.

These blog pages are not a tutorial on LENI, but some help I hope to people using search engines to find out more information on the standard. Anyway...

Summarizing, very roughly:

The bigger the number the worse the value is, it means more energy is being used for lighting. So:

Low LENI = Good
High LENI = Bad

Now a bit more detail about the W in the above formula:

Now if we look at WL,t closer:

We are starting to go down the rabbit hole which is the complex arrangement of nested formulas in LENI. I'll be explaining the other terms over the next few blog posts.

To finish this post though here are some definitions of the various "types" of "LENI":

·	LENI = Annual LENI of the whole building, the most important.

·	sub-LENI = Annual LENI of a particular floor, room, or zone. It and gives details of the consumption within the building areas

Specific Energy = Energy divided by area per month (or maybe even day hour) of the building, floor, room, or zone.

That said LENI (= Annual LENI) is the most important one.

Here is a more detailed look at some of those formulas.

LeniCalc, a program to do the calculation for you!

Ransen's Lighting Energy Numeric Indicator (LENI) Blog

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