Is there a creative way to squeeze more heat out of this small radiator

Reply

  #1  
Old 11-02-20, 06:27 PM
D
Member
Thread Starter
Join Date: Nov 2003
Location: USA
Posts: 284
Received 0 Votes on 0 Posts
Is there a creative way to squeeze more heat out of this small radiator

Some background - I own this multifamily house and live in the 3rd flr. Singly metered, the steam boiler services all three floors. This top floor, although very well insulated only has two radiators. The smaller radiator that I am focusing on, it relatively quickly heats up and then the vent heats up and closes off. So once shut off with the heating cycle still having another 15 minutes of steam, no new steam enters the radiator. The radiator just radiates the existing steam energy it received until the vent shut off. If this were a larger radiator - one that had more fins, it would take a much longer time for the heat to reach the vent and heat it up and close off. Thus allowing new steam to keep entering the radiator for most or all of the heating cycle, thus radiating more heat into the apt.

I am trying to be creative, trying to enable this small radiator to transfer some more heat than it has been doing so far. One idea is to place a heat sensor to turn on and control a small fan to blow air across a few of the fins, which would include the fin the vent is screwed into. In this way increasing heat transfer to the apt and allowing more steam into the radiator because with the cool air blown across a few fins and the vent, (1) those cooled fins would transfer more steam heat than it would otherwise and the vent would either not shut off or the shutoff time would be delayed. That is my idea. Any thoughts? Or any other solutions?

Like maybe I should get somewhat of a larger radiator you will probably say. Well these are the original 200 year old radiators, recently sanded and spray painted. I guess I would prefer not getting a new or refurbished old radiator. I guess they would come with a guarantee. I would have to be certain they would mate with the valve stem too...

Much thanks!


 
  #2  
Old 11-02-20, 06:36 PM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 24,457
Received 752 Votes on 691 Posts
Well you've done well with the paint color. After that I'd get a small fan and have it blowing over the radiator. I wouldn't bother controlling the fan. Just let it run 20/7.
 
  #3  
Old 11-02-20, 07:39 PM
D
Member
Join Date: Apr 2014
Location: us
Posts: 999
Received 36 Votes on 34 Posts
Use adjustable high out put vent.
https://www.supplyhouse.com/Varivalv...alve-3840000-p

Put small boxer fan under radiator. I use them in enclosures activated by sensor clamped to pipe.

Our kitchen Thermopane picture window is 30 square foot, monster heat loss. Have 4 quiet boxer fans strung under 48" long, enclosed heating element. Works great.
 
  #4  
Old 11-02-20, 08:18 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,896
Received 1,343 Votes on 1,241 Posts
If you didn't want to leave the fan run all the time you could use a self contained thermostat. It plugs in and the fan plugs into it. It has a remote sensor you could put near the radiator.
One example - thermostat controller

You could find small boxer fans on ebay as well as amazon.
http://Boxer fans
 
  #5  
Old 11-03-20, 02:43 PM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,295
Received 109 Votes on 101 Posts
A fan blowing over a steam radiator should increase the heat output significantly during the heating cycle. For maximum heat the fan should not be too small and should play over all of the radiator fins or lobes, blowing air more or less upwards.

When the boiler first turns on, steam enters the radiator and condenses on the inside, heating up the radiator and also leaving "room" for more steam. If/when the inside of the radiator reaches 212 degrees F (or perhaps a few more degrees depending on the system operating pressure) the steam inside stops condensing and the radiator then stops accepting more steam.

Circulating more room air more quickly over the radiator causes the air to pick up heat more rapidly and the radiator in turn to cool down causing it to condense more steam within more rapidly and admit more new steam during the limited boiler heating cycle.

The purpose of the vent is to let (plain) air in and out. If air is not let out then little or no steam will ever enter the radiator. Either temperature or moisture is used to shut the vent when most of the air has been expelled during the heating cycle. This prevents steam from escaping into the room, which raises the humidity of the room intolerably and also forces the system to admit more water (if it can from the water plumbing via a refill valve) to make more steam with. When the steam condenses in the radiator and boiler is not supplying any more then a partial vacuum develops inside and air must be admitted to prevent pipe joint seals from breaking or to prevent some component somewhere in the system from collapsing due to high suction.
 

Last edited by AllanJ; 11-03-20 at 03:24 PM.
  #6  
Old 11-04-20, 10:13 AM
D
Member
Thread Starter
Join Date: Nov 2003
Location: USA
Posts: 284
Received 0 Votes on 0 Posts
Pilot Dane
Thank you. Yes definitely fans. Probably multiple ones or an inline fan that I fashion metal tubes to route the air flow(s).

Doughess
VariVent. Just put it on the radiator, thank you. And the possibility of using box fans, thank you.

PJMax.
Thx for the link to the thermostat. Yep will want to use it to operate the fans only during the heating cycle.

AllanJ
Thx for the confirmation about extracting more heat.

Question: Increased air flow via all the radiator fins, not only for maximum increase in heat transfer, but this is because we want to avoid a temperature differential between the different radiator fins? To avoid maybe damage to the joints...?
Contemplation: Your point taken regarding when the vent closes. However in this case with the 13 radiators in this house I suspect that should not ever be an issue because there will always be at lease three (of the largest) radiators that have open vents because the heat never makes it fully over to the vents. Thus, a damaging vacuum situation would not happen in any of my radiators as the entire system will never be fully closed because of this.


Seriously I love this forum! Thank you all! I get such great ideas and confirmation and critique.
 
  #7  
Old 11-04-20, 06:30 PM
G
Member
Join Date: Oct 2008
Location: USA
Posts: 3,005
Received 13 Votes on 13 Posts
Maybe increase the flow rate thru rad?

Is this a hot-water or steam system?
 
  #8  
Old 11-04-20, 07:54 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,896
Received 1,343 Votes on 1,241 Posts
Singly metered, the steam boiler services all three floors.
 
  #9  
Old 11-05-20, 09:32 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,295
Received 109 Votes on 101 Posts
The purpose of the fan is just to transfer heat from the radiator more rapidly. This in turn causes more heat (in the form of additional steam) to be provided, if available, compared with no fan.

The fan as desribed here also works for hydronic system.

Incidentally the increased air flow created by the fan should not rub against a cold surface such as a window. A plastic sheet storm window or even a sheet or other cloth might be useful.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: