Hot Property News Letter – February 2011

Welcome to this issue of the Hot Property news letter which we hope you find informative and helpful. If you have any suggestions, comments or questions, which we can address in future issues, you can contact us at info@hotpropertyspain.net

1: THE BLOKE IN THE CORNER

As 2011 is well under way, I wonder how many of our readers, can honestly say that they are still keeping up with their New Year Resolutions when in fact I, as many others, break the same resolutions every year.

So this year, when the financial climate is so unsettled, I set myself some sensible goals, which up to now I have managed to keep. So I thought that I would share one of them with you.

Saving money, or should I say not wasting money, is number one and should be an easy one to keep, particularly if it allows for a few treats later on and I hope to achieve this buy doing the following.

Keeping to the designated speed limit, using a light right foot and also turning off the air conditioning in the car, which should save around 40€ p.a.

As it is now winter, I have turned off the swimming pool pump, which is rated at 1kw. Therefore, at 3 hours per day, for say 4 months = 360kw hours, which should save around 50€

On the subject of electricity, I have replaced the dozen outside lights to my villa with low energy lamps, saving another potential 1.1kw. When comparing 100watt bulbs with 4watt lamps, with consumption over the year of an average 8 hours per day for 365 days = 2,920 hours at 1.1kw = 3,212kw hours, which should save around 449€.

Furthermore, I will also replace the bulbs to internal lamps, where appropriate, with alternative low energy lamps so increasing potential savings.

My garden, as many others, has an automatic irrigation system, but in the winter when we have adequate natural rain, I turn it off and only use it as needed, this should save on average another 100€ over the winter period.

I have also considered changing telephone supplier, but this is a minefield best avoided, particularly when every supplier finds a different way of charging for service and calls and, with many different offers available, making a straight comparison is very difficult, unless you have the brain capacity of Einstein to work it out.

The only way to make savings is to use the phone less or to, as I do at home, purchase a phone card from a local newsagent, which seems to be very economic. Obviously, you have to pay for line rental but not for calls. These phone companies, I believe, have buying power and therefore get better deals from Telefonica then I can and, therefore, they make a profit through the cost of the card and I estimate that I can save 30€ per month, (Depending on how long my wife chats to her friends in England) When adding all of the above, the estimated savings (based on current electricity charges, which are just about to increase) per year totals 669€, which is well worth the effort.

2: FREE ENERGY (LOWERING YOUR CARBON FOOT PRINT)

It is true to say that nothing is ever free. However, once the initial capital outlay is made, there are systems that will provide free energy, e.g. wind, solar and heat pumps, or at least at very low running costs.

Most readers will have heard of Wind and Solar power but heat pumps are not as common so, by explanation, a heat pump is a machine or device that moves heat from one location (the 'source') to another location (the 'sink' or 'heat sink'), using mechanical work.

Most heat pump technology moves heat from a low temperature heat source to a higher temperature heat sink. Heat pumps can provide space heating, cooling, water heating and sometimes exhaust air heat recovery.

The difference between a heat pump and a normal air conditioner is that a heat pump can be used to provide heating or cooling. Even though the heat pump can heat, it still uses the same basic refrigeration cycle to do this. In other words a heat pump can change which coil is the condenser and which the evaporator. This is normally achieved by a reversing valve. In the cooler Northern European countries, it is common to have heat pumps that are designed only to provide heating.

Common examples are domestic refrigerators, freezers, air conditioners and reversible-cycle heat pumps for providing building space heating.

Many heat pumps also use an auxiliary heat source for heating mode. This means that, even though the heat pump is the primary source of heat, another form is available as a back-up. Electricity, oil, or is are the most common source. This is put in place so that if the heat pump fails or can't provide enough heat, the auxiliary heat will kick on to make up the difference.

Geothermal heat pumps use the ground and water to work as the condensers and evaporators. They work in the same manner as an air to air heat pump but, instead of indoor and outdoor coils, they use the earth as natural evaporators and condensers. These are very eco-friendly and are a cheaper alternative in the long run, due to lower operating cost.

However, installing these items retrospectively in properties can be problematic, as to ensure effective application requires effective thermal insulation levels, which may not be possible in older properties, or at least not without a major rebuild.

Where it is to be used in new construction and with proper forethought, it should be possible to take heat from the source i.e. the ground or the sun and use it to heat the water for the hot tap or the swimming pool to extend the use of the pool into the spring and autumn, or the internal rooms of the property in the winter.

Without the intention of getting too technical, when comparing the performance of heat pumps, it is best to avoid the word "efficiency" which has a very specific thermodynamic definition. The term coefficient of performance (COP) is a better term to describe the ratio of useful heat movement to work input. Most vapor-compression heat pumps utilise electrically powered motors for their work input.

When used for heating a building on a mild day of say 10 °C, a typical air-source heat pump has a COP of 3 to 4, whereas a typical electric resistance heater has a COP of 1.0. That is, one joule of electrical energy will cause a resistance heater to produce one joule of useful heat, while under ideal conditions, one joule of electrical energy can cause a heat pump to move much more than one joule of heat from a cooler place to a warmer place, in fact heat pumps have been known to achieve a factor of 6 times the input.

Note that the heat pump is more efficient on average in hotter climates than cooler ones, so when the weather is much warmer (in a desert city or southern city) the unit will perform better than average COP. Conversely, in cold weather, the COP approaches 1. Thus, when there is a wide temperature differential on a hot day,the COP is higher than average (better).

When there is a high temperature differential on a cold day, e.g. when an air-source heat pump is used to heat a house on a very cold winter day of say 0 °C, it takes more work to move the same amount of heat indoors than on a mild day due to Carnot efficiency limits.

The Carnot cycle is a particular thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded by Benoit Paul Émile Clapeyron in the 1830s and 40s. It is the most efficient existing cycle capable of converting a given amount of thermal energy into work or, conversely, creating a temperature difference (e.g. for refrigeration) by doing a given amount of work. Every thermodynamic system exists in a particular thermodynamic state. When a system is taken through a series of different states and finally returned to its initial state, a thermodynamic cycle is said to have occurred. In the process of going through this cycle, the system may perform work on its surroundings, thereby acting as a heat engine. A system undergoing a Carnot cycle is called a Carnot heat engine, although such a 'perfect' engine is only theoretical and cannot be built in practice.

The heat pump's performance will approach 1.0 as the outdoor-to-indoor temperature difference increases for colder climates (temperature gets colder). This typically occurs around −18 °C (0 °F) outdoor temperature for air source heat pumps. Also, as the heat pump takes heat out of the air, some moisture in the outdoor air may condense and possibly freeze on the outdoor heat exchanger. The system must periodically melt this ice. In other words, when it is extremely cold outside, it is simpler and wears the machine less, to heat using an electric-resistance heater than to strain an air-source heat pump.

Geothermal heat pumps on the other hand, are dependent upon the temperature underground, which is "mild" (typically 10 °C at a depth of more than 1.5m for the UK) all year round. Their COP is therefore is normally in the range of 4.0 to 5.0.

The design of the evaporator and condenser heat exchangers is also very important to the overall efficiency of the heat pump. The heat exchange surface areas and the corresponding temperature differential (between the refrigerant and the air stream) directly affect the operating pressures and hence the work the compressor has to do in order to provide the same heating or cooling effect. Generally the larger the heat exchanger, the lower the temperature differential and the more efficient the system. Since heat exchangers are expensive, and the heat pump industry generally competes on price rather than efficiency, the drive towards more efficient heat pumps and air conditioners is often led by legislative measures on minimum efficiency standards.

In cooling mode a heat pump's operating performance is described as its energy efficiency ratio (EER) or seasonal energy efficiency ratio (SEER), and both measures have units of BTU/(h•W) (1 BTU/(h•W) = 0.293 W/W). A larger EER number indicates better performance. The manufacturer's literature should provide both a COP to describe performance in heating mode and an EER or SEER to describe performance in cooling mode. Actual performance varies, however, and depends on many factors such as installation, temperature differences, site elevation, and maintenance.

Heat pumps are more effective for heating than for cooling if the temperature difference is held equal. This is because the compressor's input energy is largely converted to useful heat when in heating mode and is discharged along with the moved heat via the condenser. But for cooling, the condenser is normally outdoors, and the compressor's dissipated work is rejected rather than put to a useful purpose.

For the same reason, opening a food refrigerator or freezer heats up the room rather than cooling it because its refrigeration cycle rejects heat to the indoor air. This heat includes the compressor's dissipated work as well as the heat removed from the inside of the appliance.

The COP increases as the temperature difference, or "lift", decreases between heat source and destination. The COP can be maximised at design time by choosing a heating system requiring only a low final water temperature (e.g. under-floor heating), and by choosing a heat source with a high average temperature (e.g. the ground). Domestic hot water (DHW) and radiators require high water temperatures, affecting the choice of heat pump technology.

So, if you are considering installing central heating, or heating your pool to extend the use of your pool from the early spring to the autumn, then you might like to consider making use of the wasted energy from the sun and in the long term save money and lower your carbon footprint.

This newsletter is intended as a guide and to be informative and helpful in the process of searching for and purchasing a property in Spain. Total accuracy cannot be guaranteed and in all legal, fiscal and other matters a fully qualified professional should be consulted. Reproduction of any part of this newsletter is not permitted without written permission.