Regular maintenance

Regular maintenance for steam radiators depends on whether the radiator is a one-pipe system (the pipe that supplies steam also returns condensate) or a two-pipe system (a separate pipe returns condensate). One-pipe systems use automatic air vents on each radiator, which bleed air as steam fills the system and then shut automatically when steam reaches the vent. A clogged air vent will keep a steam radiator from heating up. An air vent stuck open allows steam to continually escape to the living space, raising relative humidity and wasting fuel. Air vents can sometimes be cleaned by boiling them in a water and vinegar solution, but usually need to be replaced.

Steam radiators can also warp the floor they are sitting on and their thermal expansion and contraction over time can dig ruts into the floor. Both of these effects can cause the radiator to tilt, preventing water from properly draining from the radiator when it cools. This will cause banging noises when the radiator is heating up. Shims should be inserted under radiators to pitch them slightly toward the pipe in a one-pipe system or toward the steam trap in a two-pipe system.

STEAM RADIATORS

STEAM RADIATORS

Steam heating is one of the oldest heating technologies, but the process of boiling and condensing water is inherently less efficient than more modern systems, plus it typically suffers from significant lag times between the boiler turning on and the heat arriving in the radiators. As a result, steam systems make it difficult to implement control strategies such as a night setback system.

The first central heating systems for buildings used steam distribution because steam moves itself through piping without the use of pumps. Non-insulated steam pipes often deliver unwanted heat to unfinished areas, making fiberglass pipe insulation -- which can withstand high temperatures—very cost-effective.

MAINTAINING AND UPGRADING EXISTING DUCT SYSTEMS

MAINTAINING AND UPGRADING EXISTING DUCT SYSTEMS

Aside from sealing your ducts, the simplest and most effective means of maintaining your air distribution system is to assure that furniture and other objects are not blocking the airflow through your registers, and to vacuum the registers to remove any dust buildup.

Existing duct systems often suffer from design deficiencies in the return air system, and modifications by the homeowner (or just a tendency to keep doors closed) may contribute to these problems. Any rooms with a lack of sufficient return airflow may benefit from relatively simple upgrades, such as the installation of new return-air grilles, undercutting doors for return air, or installing a jumper duct.

At a colder outdoor

Karlsson [8]. At a colder outdoor temperature, the supply temperature should peak; this makes the test scheme tables in EN 14511 deficient. Also other heat distribution systems, such as under floor heating, and mixed systems should be included in the model.
 Part load performance of the heat pump must be properly taken into account, and be based on relevant testing standards.
Night set back is a choice in some calculation models; this is not relevant for heat pumps and should not be a part in a new calculation model.
 Back up heaters is sometimes necessary to complete the energy demand of the house. Back up heaters should be included in the calculation model. Supplementary heating should be possible to choose between different sources of supplementary heat, e.g. electricity, solar or biomass heating.

The possibility

The possibility to include the production of domestic hot water to the SPF calculations is also a necessity in future calculation models. It should also be described how this shall be measured in tests alternatively, how the amount of produced domestic hot water shall be estimated. Today there are two main ways how to do the measurements, including the losses or not (one can measure the amount of energy that is obtained by tappings or the amount of tap water the heat pump is producing). A lot of work has already been done in this respect in the IEA HPP Annex 28 [13]. Also, there is a CEN standard on the way on how to treat DHW production. This standard however does not take into consideration combined heating and DHW production.
 Accumulators should be possible to include in the model.  
 A model must contain clear system boundaries for what is to be included in the calculations and how measurements are performed. As a basis, the system boundaries presented in the SEPEMO project [12] is recommended.
 The model must be transparent so it is possible to follow and understand the calculations. The studied models all contain parts that are more or less transparent. For example how the estimation of the number of equivalent heating hours is performed is not shown in any method

An outcome of the results

An outcome of the results should be to see that a properly sized heat pump is the best alternative to install. An oversized heat pump will result in unnecessary on/off cycling losses and an undersized heat pump will result in unnecessary high back-up heating.
For the calculation, either BIN methods or hour by hour calculations could be used. The existing calculation models based on heat pump performance testing according to standards are all using BIN models. Therefore, to keep a clear connection to existing test standards, it is the easiest to base a new model on BIN models. A hybrid model using chronological BIN’s could also be an interesting option to look into.
The drawback with this approach might be that dynamic effects, especially in cases with large or well stratified accumulators are not treated in a way that the full potential of these units are revealed. In the proposed IEA Annex, a thorough investigation of the positive and negative effects of these approaches should be performed

Conclusions

Conclusions
For a new calculation method to better represent real SPF values there is a need to rely on consistent sets of performance data acquired from lab testing. These lab testings guarantee consistency, repeatability and reliability.  
If the objective is to give better values for individual houses, more details on the building envelope, climate data etc. must be provided for the specific setup.  
If the objective is to give reliable values for typical conditions, type houses in type climates should be used, but with better details than currently used in existing model