Designing the optimal boiler system
Non-condensing boilers can only work if the water returned to the boiler doesn’t drop below the dew point of the moisture in the flue gas. Condensation of the flu gas can cause significant boiler corrosion while too high a temperature difference results in thermal shock..
Condensing boilers, meanwhile, must be able to achieve condensation of exhaust gas on the heat exchanger to run efficiently. If the temperature of the water returning to the boiler is too high, little or no condensation is possible.
Non-condensing boilers can use the TPE3 and an added temperature sensor instead of using a normal shunt pump running at full speed. The sensor measures the temperature of the water returning to the boiler, and ensures the right temperature is maintained at all times. This secures optimum boiler protection and reduces cost of operation.
Condensing boilers can benefit from FLOWLIMIT technology as it sets the maximum system flow in order to maintain the right return temperature and allow for condensation. This ensures higher operation efficiency by utilising the latent heat potential.
Modern shunt pumps and variable frequency drives for non-condensing boilers can be configured and controlled in a number of ways. Discover the intelligent solution here.
Choose the intelligent solution
A high return water temperature gives you safe operation. But make it too high and efficiency suffers.
A shunt in a conventional boiler keeps the return water temperature above the flue gas dew point, avoiding corrosion and thermal shock.
Optimal regulation of the shunt pump is achieved by system sensors monitoring supply water temperature, TF, and return water temperature, TR. This allows the pump to react to changes in these values, regulating flow when TR reaches either minimum or maximum threshold. In addition to this, it evaluates the differential temperature across the boiler, ΔT = TF– TR, giving a warning when the set limit is exceeded.
TPE3 has all the built-in functions allowing for optimal boiler shunt control, guaranteeing you boiler efficiency and peace of mind that it operates safely.
Keeping return temperature low is key to efficiency. The solution is intelligent pump regulation.
A condensing boiler can typically increase efficiency by up to 10-12% compared to a conventional boiler. But the gain in effectiveness depends largely on the return water temperature, TR. The lower TR, the better the recovery of latent heat of vaporisation, and hereby better boiler efficiency.
TR depends on the system flow, and determining the correct duty point therefore relates directly to the fuel economy of the boiler. But predicting the pressure loss in the system can be a challenge. FLOWLIMIT in TPE3 offers the intelligent solution to this by setting a maximum system flow. This shifts the duty point, ensuring optimal temperatures for condensation of flue gasses.
- The right water temperatures are always guaranteed
- Temperatures can be read out and documented with Grundfos GO
- Design and specification is simpler as everything is based on temperatures
- No need for pump throttling valves
- Reduced pump operating costs