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Commercial Heating and hot water performance

August 16, 2021

Bespoke home and business heat solutions

A guide to how your property could be flushing profits down the drain 

Assess your control strategy 

There are many ways of fine-tuning heat and hot water control which in turn generate savings. These can be complex to set up initially and even if correctly optimised to the system they can fall out over time as building use changes and/or extensions are built.  Refining the settings on these controls can pose a great opportunity to reduce consumption and as with all these points, even very small, basic and simple adjustments can result in great savings. 

One of the simplest ways to decrease fuel use is to check that the time and temperature controls are correctly set.  Often the thermostats are set high on space heating or hot water, simply turning them down slightly can save instantly.  Similarly, if temperatures are not set high enough then run times could be elongated or even never turned off.  Another issue could be that use times have altered, meaning you are now heating zones to late in the day or too early.  

Once the basics are sorted the fine tuning of BMS systems and proprietary controls can commence.  Many auxiliary components need to be checked such as outside weather sensors and internal reference sensors.  Once these are verified the weather compensation curves and optimised start and stop can be adjusted for example. 

System water analysis 

Maintaining system water quality is essential to ensure minimal down time of systems and costs of repairs. Not only will dirty system water damage valves and components within a system, it also exacerbates the issue of corrosion itself by making the water more corrosive. Noise and clunking can also be a symptom of dirt, leading to workplace distractions or customer complaints.  Dirt in the emitters (radiators etc) affect their ability to output heat, to compensate they often require a higher flow temperature which burns more fuel and is detrimental for the system in general due to the extreme heating and cooling of the system. These higher temperatures can lead to discomfort, inefficiency and a health and safety risk.  

System fill water should also be considered, hard water or high fill volume resulting from leaks on large systems can lead to scaling of the heating exchangers. This scale forms an insulative layer which prevents the heat from getting in to the system water, lowering efficiency over time. Even with good fill water, and little to no leaks, this is unavoidable on older systems and rarely accounted for when assessing system efficiency. In addition, hard water can increase corrosion due to its increased conductivity aiding in electrolytic corrosion. 

Measuring the rate at which the system is topping up could show water wastage or a leak that may be causing damage in addition to the issues caused by scale. Analysing this and putting in a maintenance schedule can protect against all these unnecessary issues, down time and expense. 

Bypassing 

It is not uncommon for failed or incorrectly set valves to allow constant flow to a cylinder or an area that should not be heated.  This can also be a controls issue and falls partially under the balancing section. Purpose built bypass valves should be of the automatic type however they are often permanently open, again leading to higher system temperatures and wasted energy, especially if incorrectly set. 

Balancing 

One of the most basic and beneficial measures to both small and large heating systems is to effectively balance the flow to each emitter within a system.  An unbalanced system gives wasted electrical energy from excessive pumping, an uneven heat up and cool down of the system, over heating of some sections of the property and under heating in others, and system noise from excessive velocity.  Specific differentials need to be set for boilers, fan coils, radiators and underfloor heating. Checking thermostatic radiator valves are both installed and operating effectively is also beneficial here. 

Secondary circulation pipework 

The secondary circulation is a common area for efficiency loss, it is a simple hot water pipe running to a far end of the property to minimise hot water delivery time.  It is important to ensure that the pipework is correctly balanced and that the flow rate is not excessive as this to leads to noise, erosion corrosion and unnecessary energy wastage.  Likewise, underflow will mean the water temperature returns too low leading to legionella risk. It is also important to check this pipework is lagged to protect against heat loss. 

Thermal imaging inspection of plant, pipes and building fabric 

We often find that although a building seems well insulated there are weak points. These can be blown double glazing, missing or dropped insulation, cracks or poorly fitting windows and doors. Finding these points and offering something as simple as draft exclusion or filler can add up to a very noticeable saving. As well as checking the outside of a building with thermal imaging equipment for heat leaks we can also check the effectiveness of hot water stores, lagging on pipes in uninsulated areas as well as items such as commercial fridges/freezers. 

Heat loss calculation to ascertain the suitability of the boilers (oversized / undersized) 

It is worryingly common to find a boiler or hot water calorifier to be drastically oversized, the issues associated with oversized hot water is clear as the amount of fuel required is higher due to greater standing losses.  A major issue with oversizing a heat source is the increased cycling caused by low load conditions. The increased cycling (switching on and off of the boilers) gives larger over and undershooting of both internal room temperatures and within the boiler plant itself. This leads to thermal stress of the components and shortened lifespan but also more fuel usage.  

Over-sized heat sources are also common as building fabrics tend to improve over time, extra insulation and double glazing being simple examples.  There are however some adjustments that can be made to most systems controls, for example cycle rate and set point limits. 

All of these and more are included in our audits and/or service contracts, most of the above will only need to be performed once at the beginning of a service contract but should be monitored by a competent person/s over time. 

Service contracts 

Regular and full servicing of the plant and controls is not only essential for maintaining the correct mechanical operation and safety but also fuel efficiency. You want your system to last, boiler fuel efficiency is important but the full and log life-time of a system is better. Service contracts should address the areas above, many don’t offer these full services and simply tick the safety box only addressing the bare minimum. Most are not preventative maintenance contacts but simple basic servicing. 

  

Regular preventative maintenance visits - Depending on the type of property and the equipment within we recommend at least two major visits each year and ideally two shorter interim visits as well. 

Water protection program - As above water quality should be taken seriously as it is the biggest cause of degradation of hydraulic equipment.  Leaks alone can destroy a plant room, as the water is replaced by a header tank or pressurisation unit it drags in limescale and other contaminants which get to work on degradation of your system. 

Full annual safety certification - Most properties require gas safety inspections and certification to not only give peace of mind but satisfy their insurance policies and safe-guard their clientele. offer full cloud based digital certification which not only reduces paper use but allows instant access whenever it is required. 

Reduced callout costs - Many company's (including us) have reduced callout costs for unexpected issues on systems they service. Our contract customers like that once they are with us there are no hidden costs, if you need an engineer to attend then you know we can have someone there at a pre-approved rate.  The engineer will have a list of the equipment on his PDA and is likely to have been there before.  

Installing new equipment 

There is no one panacea approach to a heating and hot water system, what is perfect for one building may not be close to appropriate in another. 

Gas boilers - Often if the property is on mains natural gas the most efficient heat source is the most obvious. Although gas is a fossil fuel it is by far the cleanest and the most easily accessible. The technology is so refined that wastage really is very low, coupled with the fact it is cheap to buy the cost of running is unbeatable.  Replacing the existing standard efficiency boilers with modern condensing boilers can reduce the gas consumption drastically not only by having a more efficient unit (older models can be as low as 50% efficient in comparison to the new 98% efficient models).  Simply replacing a boiler is not enough however, making sure the use of modulating controls is implemented will maximise the reduction of gas.  In addition to the boilers, flue heat recovery or other efficiencies can make even further improvements. 

Combined heat and power – Producing expensive electricity on site from cheap gas has clear advantages, the main issue is effectively using the waste heat generated from the process. If the property has a pool for instance they would benefit from creating their own electricity, this may also suit a property with a large hot water demand like a sports club. Another consideration however is that the property must have a large plant room or outside space for one to be built. 

Solar thermal - For small to medium properties with moderate hot water usage, solar thermal is ideal to work in conjunction with a modern gas boiler.  Some condensing boiler and solar hybrid units can be installed where space is at a premium and may suit schools and restaurants. These particular products also have the advantage of utilising the solar energy for heating as well as hot water unlike typical set ups that only pre-heat water. 

Hydrogen Fuel Cells - Businesses may benefit from combined heat and power Hydrogen fuel cells, often with gas boilers for peak load.  Fuel Cell technologies are now becoming more and more popular in areas with strict air quality measures in place.  We can help advise on Fuel Cells for any application from medium sized residential up to large commercial.  As Fuel Cells have no point of use emissions, they are incomparable to other heat and power sources. 

Project management and procurement - We take on every aspect of every project in house, from design and specification to delivery and installation there is no part out of our control.  This means our clients have complete peace of mind and are free to concentrate on their own daily tasks.

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