# How to simulate a linear Radiator (UV lamp) in the room?

Hello all!
What I’m trying to do is to see the radiation distribution of the UV lamp on the interior surfaces. When the UV lamp is mounted on the upper wall, it mainly kills germs but it is worth worrying that if the radiation hurts occupants. So I want to simulate how the lamp radiates and what the irradiance of each surface has.

How could I do this?

(1) My first idea is to use the ‘ray tracing’ component. However, it mainly uses for solar radiation and only visualize the rays without showing radiation values.
(2) Then I tried to use the daylight component in honeybee like IES Luminarie. The challenge is that it is hard to find a lamp with IES file to replace Ultraviolet lamp, since the Lux-Watt conversion is complicated.

Thank you for your help!!! I have been stuck in this problem for several days… really need your help!

Hi @tiffiena, You have identified the challenge correctly. If you want to only see the distribution you can just put a surface with Radiance `light` material and see how it will work. If you need the exact values then it starts with accurate input data. Unless you can define the light source accurately the results should be looked at as a qualitative outcome and not a quantitative one.

@tiffiena

Interesting problem. I think you’re on the right track, there’s a lot of different ways to model the geometry of radiation in Ladybug, so you can achieve this in multiple ways.

I think the simplest way to calculate the radiation that lands on an analysis from a UV lamp is to use the Surface View Analysis tool. It will compute the view factor from any point (or plane) to surfaces. In your case, if we assume your UV lamp acts like a point that radiates UV equally in all directions, then you would use the point as a lamp, and use context shading to account for occlusions from lamp shading etc.

Once you compute the view factors to the various surfaces of your interior, you can then calculate the radiation for each surface with:

``````surface_radiation = lamp_radiation * VF

where:
VF = view factor from lamp point to analysis surface.
``````

This solution is basically equivalent to the ray-tracing method that you mentioned earlier, with the only difference being the view factor component will handle all the complicated stuff of figuring out the spherical distribution of rays, and ratios of plane to sphere area.

S

I guess @mostapha and I wrote our response at the same time

That should work too. Also, I realize I assumed UV is measured in watts as radiation, but if it’s measured as a light, then my method to calculate total radiation is obviously incorrect.

Thank you @mostapha! You’re right, so I’m trying to find the right IES file now. Also I’m trying to use the forward raytracing and surface view analysis method with the input of the accurate parameters too.

Thank you @SaeranVasanthakumar ! You inspired me so much! This surface view analysis tool is helpful, and I think measuring UV in watt is better. Also in order to simulate the lamp accurately, I set the louvers of the fixture as reflective material and use forward raytracing. Looks like it’s going to work!

Hi, I am now working exatly on a similar problem. I wonder which solution suggestion did you choose? Thanks in advance for your reply! BTW, I am quite new in this tool, any support will be welcome!

Hi! I finally got a good IES file, then just used the lamp as the light source for electric light simulation.