5 ways to a successful heat pump deployment – #3 Reducing system operating temperatures

The decarbonisation of the public sector is crucial when making a change for the better for our climate. To help England along, the government is giving it another push in the back with a third round of thePublic Sector Decarbonisation Scheme.  Next on the list for ultimate deployment of a low carbon heat pump installation? Taking advantage of legacy system over-sizing!

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The real legacy of your heating and solutions

Remember the first blog in this series? Where we talked about optimal sizing and said size really does matter? (If not, make sure to read that one as well!) We really meant it! Optimal sizing is everything. In case of a new building, we can make sure the system is the right size to start with.

But what about existing buildings?These systems are already built and set into place. In a study we conducted of22 renovation projects, we found that installations were oversized on an average of 95%, some even more than 200%. And while often a lot of attention is paid to maximising source temperatures in heat pump installations, the most impactful tactic to optimal efficiency, is lowering the system’s operating temperatures.

Typically to achieve this, the sizeof radiators and other heat emitters needs to be increased.  However, in existing buildings, we can take advantage of the legacy over-sizing in the pipework, distribution systems and heat emitters, to operated the installation at overall operating temperatures and therefore increase heat pump efficiency.

In short, legacy oversizing means that existing pipework and heat emitters can deliver the necessary heating load at lower flow temperatures. Granted, this must be done by correctly measuring, calculating, and simulating the system’s performance.

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Here we have an installation that is designed to deliver 150kW at a certain flow rate and design flow/return operating temperatures of 75/65⁰C.  However, due to the typical approach we see to heating system design, we can measure that this installation is 50%over sized.  I.e., even on a worst-case winters day, when the full heating power is needed, the radiator only needs to produce 100kW to meet the heat load.

This means that to deliver this100kW with the radiator that’s already installed, it’s possible to reduce the operating temperatures to (for example) 60/53⁰C – far more suitable for a heat pump.  Or indeed, deliver the same flow temperature but at a wider delta Tand lower flow rate; or a calculated combination of the two.

Knowing what the real peak heat load demands are, is the start of everything. By using a digital model, to dynamically simulate performance, we make it possible to determine the optimal system operating temperatures. This way, you will still achieve the required level of thermal comfort, demanded response and suitability for your heat pumps.

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Calculating our way to perfect optimisation

Coordination and expertise are key when successfully implementing low carbon heat solutions. To address these challenges, Hysopt has developed tools and personal dedication to analyse challenges and implementing solutions that benefit both your company and our environment.