Estimating trainer 'effort above the flat' by heart rate + cadence
Might I enquire your age?   This answer will be a bit vague without that, but you can work it out backwards.

The rule of thumb says that your max heart rate is 220-(your age in years)    I'm 40, so 180 would be my "100%" heart rate.   

This table shows cycling


This chart shows the "zones"



So your 130 BPM is likely to be the "weight loss zone" for under 50 or the Aerobic zone for over 50.

Back to cycling, my "tempo" zone would be 70-80% of 180, so 126-144 BPM.

Here's a short ride from last week - heart rate was above 160 for at least half, and a peak of 173.  That translates to higher threshhold and into VO2, which is pretty good, giving speeds of mid 30km/h to a peak of 42 km/h.  https://www.strava.com/activities/757787829/analysis



So to summarise - 130 BPM is a good "endurance" workout.   You'd need to be doing that speed for a couple hours, and frankly that's boring on a trainer.

If you're dead against training on the road, try riding at a velodrome or some other kind of off-road track.  An athletic track may work, or around the local park?   

If you can work a decent climb into your trip then that will be excellent exercise.  Use a tool like strava to measure your gains, cos it never feels faster.