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Viewing 15 posts - 31 through 45 (of 983 total)
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  • in reply to: Convincing a Lighting Skeptic #38583
    Nick Grant
    Participant

      Hi Toby

      Had the same objections plus aesthetics from a very switched on client some years ago so ended up designing some fittings for the job with a friend, Colin Chetwood, who makes lights. The friend had also been biased against CFLs and linear fluorescents but has now embraced them!

      http://www.colinchetwood.co.uk/section181470.html

      I like T5s (obviously high frequency ballasts) and you can get warm or cool white as well as dim-able. Simple pelmet fittings can be good for ambience but if you need good work lighting then likely to be suspended with mix of down and up light, great for craft work without shadows.

      Nick

      in reply to: Built-up EPS foundation tub #38363
      Nick Grant
      Participant

        Did exactly what you describe over 10 years ago based on pencil and paper calcs by structural engineer Alan Pearce in Leominster. Bob Johnston (structural engineer) http://m.bjse.co.uk/ has designed a few of these now as have others. Shouldn't be a problem for any structural engineer.

        Nick Grant
        Participant

          5 is the figure in my head but it's a bit academic given all the other variables that ae also important such as eliminating air leakage, driving rain etc.

          in reply to: Floor Insulation – Help needed #38515
          Nick Grant
          Participant

            I'd consider putting the pipe direct in the slab but with these levels of insulation I assume the building is Passivhaus. This means you won't want the floor to be warm, just a degree or 2 above room temperature but that's another discsussion that I think is somewhere on the forum!

            Nick

            in reply to: PHPP and Terraced Houses #38479
            Nick Grant
            Participant

              1. Supply should equal extract.

              Probably tricky as I assume occupancy varies a lot. A danger in over ventilating in winter when occupancy low, leads to dry air.

              ncant help beyond that but a competent equipment supplier should be able to advise.

              in reply to: TFA Question-Landings #38182
              Nick Grant
              Participant

                Cupboard part way up the stairs?

                For domestic, landings at top and bottom are included, only landings on way up the stairs are excluded.

                I would include the cupboard.

                For non-dom, circulation is 60%, stairs and lifts zero TFA.

                Nick

                in reply to: PHPP and Terraced Houses #38476
                Nick Grant
                Participant

                  Hi Rachel

                  One thing to watch is the vent sheet if each has it's own MVHR.

                  If they are all the same it's easy. Enter the vent rate, duct length etc for one dwelling in othe vent sheet and note the calculated efficiency including duct losses.

                  Enter this in the user's own MVHR data box and call it mvhr with losses say.

                  Now put in the ventilation rate for the whole terrace and select 'mvhr with losses' as the unit. Delete the ducts and that should be it.

                  Nick

                  in reply to: DHW without circulation #38482
                  Nick Grant
                  Participant

                    Mark, what do you mean “try reading the water standard”??? 🙂

                    As Mark says the dead legs are assumed to cool 3 times per person per day. It's an approximation and close enough to inform design when choosing between circulation and short draw off or longer draw offs and no circulation.

                    However what PHPP forgets is the heat loss from circulation when the pump is off. For a non domestic building this volume can be significant and has to be reheated when the pump starts up again.

                    The draw off loss is nothing to do with whether water is wasted waiting for hot (the reason to insulate the dead legs unless micro bore). PHPP assumes a modest 25 litres per person stored hot water use and only calculates the losses as a variable.

                    The EST report we did and the Dresden Confeence paper (see my website) put some numbers on the different losses and you have the nice graph in colour in your CEPH services book!

                    HTH

                    Nick

                    in reply to: CarbonLite and the AECB Water Standards #38431
                    Nick Grant
                    Participant

                      Better check with the client re acceptability before doing sums!

                      in reply to: MVHR for small units #38468
                      Nick Grant
                      Participant

                        Hi Rachel

                        I agree with Mark re MEV.

                        Neighbour is building a tiny 8m2 well insulated guitar workshop that needs constant temp and RH. It has 300mm+ insulation all round, air tight, no thermal bridges, triple glazing etc.

                        We assumed a small single room HRV but thought we should model it in PHPP.

                        Attached shows energy balance assuming MEV and 0.37 airchanges average vent rate (higher when in use then turns off or to trickle).

                        Adding efficient MVHR would only reduce the ventilation by a bit as there is still leakage and door opening etc is more significant in tiny building.

                        Result really surprised me and I got Alan Clarke to check it.

                        So model in PHPP and be prepared for a surprise if you think you can achieve 15 kWh.m2.a or 10W/m2!

                        In practice for small buildings the internal heat gains will be higher per m2 than the assumed domestic level and you can work them out in PHPP, I didn't, my fee was a couple of pints down the pub!

                        Nick

                        in reply to: Water Supply/Management – domestic house (uk) #38445
                        Nick Grant
                        Participant

                          Yes it can be done, no I would not recommend it unless absolutely no other options which is unlikely as houses are rarely built where there was no water supply.

                          Jean de Florette was a nice film.

                          For sewage effluent, septic tank and shallow leachfield is the first choice unless close to a well which you don't seem to be, or soil is impermeable. If latter than need a stream to discharge treated effluent to.

                          Nick

                          in reply to: Re: Re: Gas boilers to be banned? #38459
                          Nick Grant
                          Participant

                            Would be interesting if boilers (gas or otherwise) over 2.5kW were banned for domestic use from 2016.

                            Might have an impact on the market!

                            in reply to: Re: Re: TAS for interstitial condensation analysis #38334
                            Nick Grant
                            Participant

                              So Mike are you really still saying that the heat loss through my floor with 4″ of insulation and 10″ of edge insulation is a figment of my imagination?

                              The ground is a a pretty constant temperature all heating season and my house is around 20C +/- couple of degrees Q=U dT?

                              Nick

                              in reply to: Re: Re: PHPP local weather data #37310
                              Nick Grant
                              Participant

                                Can download a trial version of Meteonorm and generate PHPP friendly weather data using a range of preferences.

                                Certainly the BRE data typically knocks a couple of kWh/(m2.a) of PHPP result

                                in reply to: CarbonLite and the AECB Water Standards #38429
                                Nick Grant
                                Participant

                                  you mean instantaneous electric?

                                  Just discussing this today for a new school project. Balancing distribution losses against carbon emissions of gas v electric etc.

                                  Hard to get enough flow for a kitchen sink unless higher power unit. Obviously electric is about 3 x the CO2 of gas heated water (assuming the standing cylinder losses are there anyway for other taps).

                                  20m is a bit long for microbore but might work if you have the pressure and can tolerate say 4-6 l/min flow or so.

                                  Complex solution is to use a re-cirulator pump on a switch but just to get the water to the tap when you need it. Or use the cold water run off for watering plants in summer and flushing loo in winter.

                                  The hot water left in the pipe still goes cold and the energy is wasted.

                                  All depends how often you are using the sink, how your water is heated etc.

                                  Energy in kWh lost per cool off is about = volume of water in pipe in litres x 1.16 x temp drop /1000

                                  Temp drop is from say 60C to 20C room. Obviously in the heating season this will be largely used as space heating. In PHPP we assume 3 cool offs per occupant per day.

                                  The EST water and carbon report looks at all this.

                                  Sorry not to give simple answer but all depends.

                                  Nick

                                Viewing 15 posts - 31 through 45 (of 983 total)